webtoolkit.info » Javascript

Chainable external javascript file loading

admin — Mon, 10 Jan 2011 13:14:58 +0000

This object is useful when you want to load external javascript files only when last one was loaded.

In this way you will form some sort of chainable javascript library loading, which will guarantee you that every file will be loaded only then when it has its dependencies loaded.

Usage

This example shows how to load jQuery library and only when its fully loaded then load jQuery UI library, and only then your scripts – “your-script.js”.

scriptLoader.load([
'http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js',
'http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/jquery-ui.min.js'
'your-script.js'
]);

Source of the library

/**
*
*  Chainable external javascript file loading
*  http://www.webtoolkit.info/
*
**/
var scriptLoader = {
	_loadScript: function (url, callback) {
		var head = document.getElementsByTagName('head')[0];
		var script = document.createElement('script');
		script.type = 'text/javascript';
		script.src = url;
		if (callback) {
			script.onreadystatechange = function () {
				if (this.readyState == 'loaded') callback();
			}
			script.onload = callback;
		}
		head.appendChild(script);
	},
 
	load: function (items, iteration) {
		if (!iteration) iteration = 0;
		if (items[iteration]) {
			scriptLoader._loadScript(
				items[iteration],
				function () {
					scriptLoader.load(items, iteration+1);
				}
			)
		}
	}
}

Javascript color conversion

admin — Fri, 07 Jan 2011 14:37:47 +0000

This Javascript library, will help you to convert colors between different color systems.

It supports RGB, HSV, CMYK color encoding systems.

First you need to create color object you want to convert from.

As mentioned above there are 3 types:

var obj = new RGB(10 /* red */, 20 /* green */, 30 /* blue */);
var obj = new HSV(10 /* hue */, 20 /* saturation */, 30 /* value */);
var obj = new CMYK(10 /* cyan */, 20 /* magenta */, 30 /* yellow */, 40 /* key black */);

Usage

Then you just need to pass that object to appropriate “ColorConverter” method.

To convert from HSV to RGB use library like this:

var result = ColorConverter.toRGB(new HSV(10, 20, 30));
alert("RGB:" + result.r + ":" + result.g + ":" + result.b);

Result:

To convert from RGB to HSV use library like this:

var result = ColorConverter.toHSV(new RGB(10, 20, 30));
alert("HSV:" + result.h + ":" + result.s + ":" + result.v);

Result:

Source of the library

/**
*
*  Javascript color conversion
*  http://www.webtoolkit.info/
*
**/
 
function HSV(h, s, v) {
	if (h <= 0) { h = 0; }
	if (s <= 0) { s = 0; }
	if (v <= 0) { v = 0; }
 
	if (h > 360) { h = 360; }
	if (s > 100) { s = 100; }
	if (v > 100) { v = 100; }
 
	this.h = h;
	this.s = s;
	this.v = v;
}
 
function RGB(r, g, b) {
	if (r <= 0) { r = 0; }
	if (g <= 0) { g = 0; }
	if (b <= 0) { b = 0; }
 
	if (r > 255) { r = 255; }
	if (g > 255) { g = 255; }
	if (b > 255) { b = 255; }
 
	this.r = r;
	this.g = g;
	this.b = b;
}
 
function CMYK(c, m, y, k) {
	if (c <= 0) { c = 0; }
	if (m <= 0) { m = 0; }
	if (y <= 0) { y = 0; }
	if (k <= 0) { k = 0; }
 
	if (c > 100) { c = 100; }
	if (m > 100) { m = 100; }
	if (y > 100) { y = 100; }
	if (k > 100) { k = 100; }
 
	this.c = c;
	this.m = m;
	this.y = y;
	this.k = k;
}
 
var ColorConverter = {
 
	_RGBtoHSV : function  (RGB) {
		var result = new HSV(0, 0, 0);
 
		r = RGB.r / 255;
		g = RGB.g / 255;
		b = RGB.b / 255;
 
		var minVal = Math.min(r, g, b);
		var maxVal = Math.max(r, g, b);
		var delta = maxVal - minVal;
 
		result.v = maxVal;
 
		if (delta == 0) {
			result.h = 0;
			result.s = 0;
		} else {
			result.s = delta / maxVal;
			var del_R = (((maxVal - r) / 6) + (delta / 2)) / delta;
			var del_G = (((maxVal - g) / 6) + (delta / 2)) / delta;
			var del_B = (((maxVal - b) / 6) + (delta / 2)) / delta;
 
			if (r == maxVal) { result.h = del_B - del_G; }
			else if (g == maxVal) { result.h = (1 / 3) + del_R - del_B; }
			else if (b == maxVal) { result.h = (2 / 3) + del_G - del_R; }
 
			if (result.h < 0) { result.h += 1; }
			if (result.h > 1) { result.h -= 1; }
		}
 
		result.h = Math.round(result.h * 360);
		result.s = Math.round(result.s * 100);
		result.v = Math.round(result.v * 100);
 
		return result;
	},
 
	_HSVtoRGB : function  (HSV) {
		var result = new RGB(0, 0, 0);
 
		var h = HSV.h / 360;
		var s = HSV.s / 100;
		var v = HSV.v / 100;
 
		if (s == 0) {
			result.r = v * 255;
			result.g = v * 255;
			result.v = v * 255;
		} else {
			var_h = h * 6;
			var_i = Math.floor(var_h);
			var_1 = v * (1 - s);
			var_2 = v * (1 - s * (var_h - var_i));
			var_3 = v * (1 - s * (1 - (var_h - var_i)));
 
			if (var_i == 0) {var_r = v; var_g = var_3; var_b = var_1}
			else if (var_i == 1) {var_r = var_2; var_g = v; var_b = var_1}
			else if (var_i == 2) {var_r = var_1; var_g = v; var_b = var_3}
			else if (var_i == 3) {var_r = var_1; var_g = var_2; var_b = v}
			else if (var_i == 4) {var_r = var_3; var_g = var_1; var_b = v}
			else {var_r = v; var_g = var_1; var_b = var_2};
 
			result.r = var_r * 255;
			result.g = var_g * 255;
			result.b = var_b * 255;
 
			result.r = Math.round(result.r);
			result.g = Math.round(result.g);
			result.b = Math.round(result.b);
		}
 
		return result;
	},
 
	_CMYKtoRGB : function (CMYK){
		var result = new RGB(0, 0, 0);
 
		c = CMYK.c / 100;
		m = CMYK.m / 100;
		y = CMYK.y / 100;
		k = CMYK.k / 100;
 
		result.r = 1 - Math.min( 1, c * ( 1 - k ) + k );
		result.g = 1 - Math.min( 1, m * ( 1 - k ) + k );
		result.b = 1 - Math.min( 1, y * ( 1 - k ) + k );
 
		result.r = Math.round( result.r * 255 );
		result.g = Math.round( result.g * 255 );
		result.b = Math.round( result.b * 255 );
 
		return result;
	},
 
	_RGBtoCMYK : function (RGB){
		var result = new CMYK(0, 0, 0, 0);
 
		r = RGB.r / 255;
		g = RGB.g / 255;
		b = RGB.b / 255;
 
		result.k = Math.min( 1 - r, 1 - g, 1 - b );
		result.c = ( 1 - r - result.k ) / ( 1 - result.k );
		result.m = ( 1 - g - result.k ) / ( 1 - result.k );
		result.y = ( 1 - b - result.k ) / ( 1 - result.k );
 
		result.c = Math.round( result.c * 100 );
		result.m = Math.round( result.m * 100 );
		result.y = Math.round( result.y * 100 );
		result.k = Math.round( result.k * 100 );
 
		return result;
	},
 
	toRGB : function (o) {
		if (o instanceof RGB) { return o; }
		if (o instanceof HSV) {	return this._HSVtoRGB(o); }
		if (o instanceof CMYK) { return this._CMYKtoRGB(o); }
	},
 
	toHSV : function (o) {
		if (o instanceof HSV) { return o; }
		if (o instanceof RGB) { return this._RGBtoHSV(o); }
		if (o instanceof CMYK) { return this._RGBtoHSV(this._CMYKtoRGB(o)); }
	},
 
	toCMYK : function (o) {
		if (o instanceof CMYK) { return o; }
		if (o instanceof RGB) { return this._RGBtoCMYK(o); }
		if (o instanceof HSV) { return this._RGBtoCMYK(this._HSVtoRGB(o)); }
	}
 
}

Javascript open popup window

admin — Wed, 22 Dec 2010 17:26:19 +0000

Javascript popup window script sometimes is useful for adding a popup window to your pages. When the user clicks on a link, a new window opens and displays a page.

You can use this function like this:

<a href="http://www.webtoolkit.info" title="Free code and tutorials"
onclick="return openWindow(this, {width:790,height:450,center:true})"
Free code and tutorials</a>

There are some available optional parameters which are passed as a second object parameter to this Javascript open window function (look above):

width
height
left
top
center
name
scrollbars
menubar
locationbar
resizable

Source code for webtookit.openwindow.js

/**
*
*  Javascript open window
*  http://www.webtoolkit.info/
*
**/
 
function openWindow(anchor, options) {
 
	var args = '';
 
	if (typeof(options) == 'undefined') { var options = new Object(); }
	if (typeof(options.name) == 'undefined') { options.name = 'win' + Math.round(Math.random()*100000); }
 
	if (typeof(options.height) != 'undefined' && typeof(options.fullscreen) == 'undefined') {
		args += "height=" + options.height + ",";
	}
 
	if (typeof(options.width) != 'undefined' && typeof(options.fullscreen) == 'undefined') {
		args += "width=" + options.width + ",";
	}
 
	if (typeof(options.fullscreen) != 'undefined') {
		args += "width=" + screen.availWidth + ",";
		args += "height=" + screen.availHeight + ",";
	}
 
	if (typeof(options.center) == 'undefined') {
		options.x = 0;
		options.y = 0;
		args += "screenx=" + options.x + ",";
		args += "screeny=" + options.y + ",";
		args += "left=" + options.x + ",";
		args += "top=" + options.y + ",";
	}
 
	if (typeof(options.center) != 'undefined' && typeof(options.fullscreen) == 'undefined') {
		options.y=Math.floor((screen.availHeight-(options.height || screen.height))/2)-(screen.height-screen.availHeight);
		options.x=Math.floor((screen.availWidth-(options.width || screen.width))/2)-(screen.width-screen.availWidth);
		args += "screenx=" + options.x + ",";
		args += "screeny=" + options.y + ",";
		args += "left=" + options.x + ",";
		args += "top=" + options.y + ",";
	}
 
	if (typeof(options.scrollbars) != 'undefined') { args += "scrollbars=1,"; }
	if (typeof(options.menubar) != 'undefined') { args += "menubar=1,"; }
	if (typeof(options.locationbar) != 'undefined') { args += "location=1,"; }
	if (typeof(options.resizable) != 'undefined') { args += "resizable=1,"; }
 
	var win = window.open(anchor, options.name, args);
	return false;
 
}

Javascript replace

admin — Sat, 11 Dec 2010 14:49:34 +0000

Javascript string replace is a very useful function. Javascript has a built-in string replace function but it uses regular expressions. Here you will fint two versions of custom string replace functions (maybe more wrappers for built-in functions).

Source code for webtoolkit.strreplace.js

/**
*
*  Javascript string replace
*  http://www.webtoolkit.info/
*
**/
 
// standart string replace functionality
function str_replace(haystack, needle, replacement) {
	var temp = haystack.split(needle);
	return temp.join(replacement);
}
 
// needle may be a regular expression
function str_replace_reg(haystack, needle, replacement) {
	var r = new RegExp(needle, 'g');
	return haystack.replace(r, replacement);
}

Sortable table

admin — Mon, 24 Aug 2009 17:58:06 +0000

This JavaScript sortable html table code can be used to convert tables in ordinary HTML into sortable ones. This script is unobtrusive. No additional coding is necessary. All you need to do is put header (sorting) row in THEAD section, table body rows in TBODY section, footer rows (if you need them) in TFOOT section and give your table an ID field, include the webtoolkit.sortabletable.js file and create SortableTable() object after each table.

Tested in IE5.0+, OP8.0+, FF1.0+

DEMO

Source code for index.html


<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
	<title>Scrollable HTML table</title>
	<meta http-equiv="Content-type" content="text/html; charset=UTF-8" />
	<script type="text/javascript" src="webtoolkit.sortabletable.js"></script>
 
	<style>
		table {
			text-align: left;
			font-size: 12px;
			font-family: verdana;
			background: #c0c0c0;
		}
 
		table thead  {
			cursor: pointer;
		}
 
		table thead tr,
		table tfoot tr {
			background: #c0c0c0;
		}
 
		table tbody tr {
			background: #f0f0f0;
		}
 
		td, th {
			border: 1px solid white;
		}
	</style>
</head>
 
<body>
 
<table cellspacing="1" cellpadding="2" class="" id="myTable" width="400">
	<thead>
		<tr>
			<th class="c1">Name</th>
			<th class="c2">Surename</th>
			<th class="c3">Age</th>
		</tr>
	</thead>
 
	<tbody>
		<tr class="r1">
			<td class="c1">John</th>
			<td class="c2">Smith</th>
			<td class="c3">30</th>
		</tr>
		<tr class="r2">
			<td class="c1">John</th>
			<td class="c2">Smith</th>
			<td class="c3">31</th>
		</tr>
		<tr class="r1">
			<td class="c1">John</th>
			<td class="c2">Smith</th>
			<td class="c3">32</th>
		</tr>
		<tr class="r2">
			<td class="c1">John</th>
			<td class="c2">Smith</th>
			<td class="c3">33</th>
		</tr>
		<tr class="r1">
			<td class="c1">John</th>
			<td class="c2">Smith</th>
			<td class="c3">34</th>
		</tr>
		<tr class="r2">
			<td class="c1">John</th>
			<td class="c2">Smith</th>
			<td class="c3">35</th>
		</tr>
		<tr class="r1">
			<td class="c1">John</th>
			<td class="c2">Smith</th>
			<td class="c3">36</th>
		</tr>
		<tr class="r2">
			<td class="c1">John</th>
			<td class="c2">Smith</th>
			<td class="c3">37</th>
		</tr>
	</tbody>
 
	<tfoot>
		<tr>
			<th class="c1">Name</th>
			<th class="c2">Surename</th>
			<th class="c3">Age</th>
		</tr>
	</tfoot>
</table>
 
<script type="text/javascript">
var t = new SortableTable(document.getElementById('myTable'), 100);
</script>
 
</body>
</html>

Source code for webtoolkit.sortabletable.js

/**
*
*  Sortable HTML table
*  http://www.webtoolkit.info/
*
**/
 
function SortableTable (tableEl) {
 
	this.tbody = tableEl.getElementsByTagName('tbody');
	this.thead = tableEl.getElementsByTagName('thead');
	this.tfoot = tableEl.getElementsByTagName('tfoot');
 
	this.getInnerText = function (el) {
		if (typeof(el.textContent) != 'undefined') return el.textContent;
		if (typeof(el.innerText) != 'undefined') return el.innerText;
		if (typeof(el.innerHTML) == 'string') return el.innerHTML.replace(/<[^<>]+>/g,'');
	}
 
	this.getParent = function (el, pTagName) {
		if (el == null) return null;
		else if (el.nodeType == 1 && el.tagName.toLowerCase() == pTagName.toLowerCase())
			return el;
		else
			return this.getParent(el.parentNode, pTagName);
	}
 
	this.sort = function (cell) {
 
	    var column = cell.cellIndex;
	    var itm = this.getInnerText(this.tbody[0].rows[1].cells[column]);
		var sortfn = this.sortCaseInsensitive;
 
		if (itm.match(/\d\d[-]+\d\d[-]+\d\d\d\d/)) sortfn = this.sortDate; // date format mm-dd-yyyy
		if (itm.replace(/^\s+|\s+$/g,"").match(/^[\d\.]+$/)) sortfn = this.sortNumeric;
 
		this.sortColumnIndex = column;
 
	    var newRows = new Array();
	    for (j = 0; j < this.tbody[0].rows.length; j++) {
			newRows[j] = this.tbody[0].rows[j];
		}
 
		newRows.sort(sortfn);
 
		if (cell.getAttribute("sortdir") == 'down') {
			newRows.reverse();
			cell.setAttribute('sortdir','up');
		} else {
			cell.setAttribute('sortdir','down');
		}
 
		for (i=0;i<newRows.length;i++) {
			this.tbody[0].appendChild(newRows[i]);
		}
 
	}
 
	this.sortCaseInsensitive = function(a,b) {
		aa = thisObject.getInnerText(a.cells[thisObject.sortColumnIndex]).toLowerCase();
		bb = thisObject.getInnerText(b.cells[thisObject.sortColumnIndex]).toLowerCase();
		if (aa==bb) return 0;
		if (aa<bb) return -1;
		return 1;
	}
 
	this.sortDate = function(a,b) {
		aa = thisObject.getInnerText(a.cells[thisObject.sortColumnIndex]);
		bb = thisObject.getInnerText(b.cells[thisObject.sortColumnIndex]);
		date1 = aa.substr(6,4)+aa.substr(3,2)+aa.substr(0,2);
		date2 = bb.substr(6,4)+bb.substr(3,2)+bb.substr(0,2);
		if (date1==date2) return 0;
		if (date1<date2) return -1;
		return 1;
	}
 
	this.sortNumeric = function(a,b) {
		aa = parseFloat(thisObject.getInnerText(a.cells[thisObject.sortColumnIndex]));
		if (isNaN(aa)) aa = 0;
		bb = parseFloat(thisObject.getInnerText(b.cells[thisObject.sortColumnIndex]));
		if (isNaN(bb)) bb = 0;
		return aa-bb;
	}
 
	// define variables
	var thisObject = this;
	var sortSection = this.thead;
 
	// constructor actions
	if (!(this.tbody && this.tbody[0].rows && this.tbody[0].rows.length > 0)) return;
 
	if (sortSection && sortSection[0].rows && sortSection[0].rows.length > 0) {
		var sortRow = sortSection[0].rows[0];
	} else {
		return;
	}
 
	for (var i=0; i<sortRow.cells.length; i++) {
		sortRow.cells[i].sTable = this;
		sortRow.cells[i].onclick = function () {
			this.sTable.sort(this);
			return false;
		}
	}
 
}

Javascript trim

admin — Fri, 26 Jun 2009 15:37:07 +0000

In programming, trim is a string manipulation function or algorithm. The most popular variants of the trim function strip only the beginning or end of the string. Typically named ltrim and rtrim respectively.

This Javascript code trim implementation removes all leading and trailing occurrences of a set of characters specified. If no characters are specified it will trim whitespace characters from the beginning or end or both of the string.

Without the second parameter, Javascript function will trim these characters:

” ” (ASCII 32 (0×20)), an ordinary space.
“\t” (ASCII 9 (0×09)), a tab.
“\n” (ASCII 10 (0x0A)), a new line (line feed).
“\r” (ASCII 13 (0x0D)), a carriage return.
“\0″ (ASCII 0 (0×00)), the NUL-byte.
“\x0B” (ASCII 11 (0x0B)), a vertical tab.

DEMO

Source code for webtoolkit.trim.js

/**
*
*  Javascript trim, ltrim, rtrim
*  http://www.webtoolkit.info/
*
**/
 
function trim(str, chars) {
	return ltrim(rtrim(str, chars), chars);
}
 
function ltrim(str, chars) {
	chars = chars || "\\s";
	return str.replace(new RegExp("^[" + chars + "]+", "g"), "");
}
 
function rtrim(str, chars) {
	chars = chars || "\\s";
	return str.replace(new RegExp("[" + chars + "]+$", "g"), "");
}

Javascript context menu

admin — Thu, 18 Jun 2009 17:38:30 +0000

There are many of context menu examples on the internet. This javascript context menu is very lightweight, OOP based and item-specific. You can setup it in a few seconds.

Include the script and the style sheet at the top of your code (you can find the code in the source code section of this page). Do it in tag. After loading the script you can write your code to attach context menu.

Javascript context menu code tested in IE5.5+, FF1.0+.

DEMO

Source code for index.html


<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
	<title>My project</title>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
	<link type="text/css" rel="stylesheet" href="webtoolkit.contextmenu.css" />
	<script type="text/javascript" src="webtoolkit.contextmenu.js"></script>
	<script type="text/javascript">
		SimpleContextMenu.setup({'preventDefault':true, 'preventForms':false});
		SimpleContextMenu.attach('container', 'CM1');
	</script>
</head>
<body>
	<ul id="CM1" class="SimpleContextMenu">
		<li><a href="#">Item 1</a></li>
		<li><a href="#">Item 2</a></li>
		<li><a href="#">Item 3</a></li>
		<li><a href="#">Item 4</a></li>
	</ul>
 
	<input type="text" name="field" value="" />
	<div class="container">Cointainer1</div>
	<div class="container">Cointainer2</div>
	<div class="container">Cointainer3</div>
</body>
</html>

Source code for webtoolkit.contextmenu.css

ul.SimpleContextMenu {
	display: none;
	position: absolute;
	margin: 0px;
	padding: 0px;
	font-family: verdana;
	font-size: 12px;
	list-style-type: none;
	border-top: 1px solid #000000;
	border-left: 1px solid #000000;
	border-right: 1px solid #000000;
}
 
	ul.SimpleContextMenu li {
		border-bottom: 1px solid #000000;
	}
 
		ul.SimpleContextMenu li a {
			display: block;
			width: 100px;
			padding: 2px 10px 3px 10px;
			text-decoration: none;
			color: #ff0000;
			background: #eeeeee;
		}
 
		ul.SimpleContextMenu li a:hover {
			text-decoration: none;
			color: #ffffff;
			background: #ff0000;
		}

Source code for webtoolkit.contextmenu.js

/**
*
*  Simple Context Menu
*  http://www.webtoolkit.info/
*
**/
 
var SimpleContextMenu = {
 
	// private attributes
	_menus : new Array,
	_attachedElement : null,
	_menuElement : null,
	_preventDefault : true,
	_preventForms : true,
 
 
	// public method. Sets up whole context menu stuff..
	setup : function (conf) {
 
		if ( document.all && document.getElementById && !window.opera ) {
			SimpleContextMenu.IE = true;
		}
 
		if ( !document.all && document.getElementById && !window.opera ) {
			SimpleContextMenu.FF = true;
		}
 
		if ( document.all && document.getElementById && window.opera ) {
			SimpleContextMenu.OP = true;
		}
 
		if ( SimpleContextMenu.IE || SimpleContextMenu.FF ) {
 
			document.oncontextmenu = SimpleContextMenu._show;
			document.onclick = SimpleContextMenu._hide;
 
			if (conf && typeof(conf.preventDefault) != "undefined") {
				SimpleContextMenu._preventDefault = conf.preventDefault;
			}
 
			if (conf && typeof(conf.preventForms) != "undefined") {
				SimpleContextMenu._preventForms = conf.preventForms;
			}
 
		}
 
	},
 
 
	// public method. Attaches context menus to specific class names
	attach : function (classNames, menuId) {
 
		if (typeof(classNames) == "string") {
			SimpleContextMenu._menus[classNames] = menuId;
		}
 
		if (typeof(classNames) == "object") {
			for (x = 0; x < classNames.length; x++) {
				SimpleContextMenu._menus[classNames[x]] = menuId;
			}
		}
 
	},
 
 
	// private method. Get which context menu to show
	_getMenuElementId : function (e) {
 
		if (SimpleContextMenu.IE) {
			SimpleContextMenu._attachedElement = event.srcElement;
		} else {
			SimpleContextMenu._attachedElement = e.target;
		}
 
		while(SimpleContextMenu._attachedElement != null) {
			var className = SimpleContextMenu._attachedElement.className;
 
			if (typeof(className) != "undefined") {
				className = className.replace(/^\s+/g, "").replace(/\s+$/g, "")
				var classArray = className.split(/[ ]+/g);
 
				for (i = 0; i < classArray.length; i++) {
					if (SimpleContextMenu._menus[classArray[i]]) {
						return SimpleContextMenu._menus[classArray[i]];
					}
				}
			}
 
			if (SimpleContextMenu.IE) {
				SimpleContextMenu._attachedElement = SimpleContextMenu._attachedElement.parentElement;
			} else {
				SimpleContextMenu._attachedElement = SimpleContextMenu._attachedElement.parentNode;
			}
		}
 
		return null;
 
	},
 
 
	// private method. Shows context menu
	_getReturnValue : function (e) {
 
		var returnValue = true;
		var evt = SimpleContextMenu.IE ? window.event : e;
 
		if (evt.button != 1) {
			if (evt.target) {
				var el = evt.target;
			} else if (evt.srcElement) {
				var el = evt.srcElement;
			}
 
			var tname = el.tagName.toLowerCase();
 
			if ((tname == "input" || tname == "textarea")) {
				if (!SimpleContextMenu._preventForms) {
					returnValue = true;
				} else {
					returnValue = false;
				}
			} else {
				if (!SimpleContextMenu._preventDefault) {
					returnValue = true;
				} else {
					returnValue = false;
				}
			}
		}
 
		return returnValue;
 
	},
 
 
	// private method. Shows context menu
	_show : function (e) {
 
		SimpleContextMenu._hide();
		var menuElementId = SimpleContextMenu._getMenuElementId(e);
 
		if (menuElementId) {
			var m = SimpleContextMenu._getMousePosition(e);
			var s = SimpleContextMenu._getScrollPosition(e);
 
			SimpleContextMenu._menuElement = document.getElementById(menuElementId);
			SimpleContextMenu._menuElement.style.left = m.x + s.x + 'px';
			SimpleContextMenu._menuElement.style.top = m.y + s.y + 'px';
			SimpleContextMenu._menuElement.style.display = 'block';
			return false;
		}
 
		return SimpleContextMenu._getReturnValue(e);
 
	},
 
 
	// private method. Hides context menu
	_hide : function () {
 
		if (SimpleContextMenu._menuElement) {
			SimpleContextMenu._menuElement.style.display = 'none';
		}
 
	},
 
 
	// private method. Returns mouse position
	_getMousePosition : function (e) {
 
		e = e ? e : window.event;
		var position = {
			'x' : e.clientX,
			'y' : e.clientY
		}
 
		return position;
 
	},
 
 
	// private method. Get document scroll position
	_getScrollPosition : function () {
 
		var x = 0;
		var y = 0;
 
		if( typeof( window.pageYOffset ) == 'number' ) {
			x = window.pageXOffset;
			y = window.pageYOffset;
		} else if( document.documentElement && ( document.documentElement.scrollLeft || document.documentElement.scrollTop ) ) {
			x = document.documentElement.scrollLeft;
			y = document.documentElement.scrollTop;
		} else if( document.body && ( document.body.scrollLeft || document.body.scrollTop ) ) {
			x = document.body.scrollLeft;
			y = document.body.scrollTop;
		}
 
		var position = {
			'x' : x,
			'y' : y
		}
 
		return position;
 
	}
 
}

Javascript image preload

admin — Thu, 18 Jun 2009 13:36:00 +0000

How to get rid of the delay that happens when you use multiple images with ‘onmouseover’? Preload all the images.

You can supply one image url as an argument to this function, or an array of image urls.

Source code for webtoolkit.imagepreload.js

/**
*
*  Image preload
*  http://www.webtoolkit.info/
*
**/
 
function ImagePreload() {
	if (typeof(arguments) != 'undefined') {
		for (i=0; i<arguments.length; i++ ) {
			if (typeof(arguments[i]) == "object") {
				for (k=0; k<arguments[i].length; k++) {
					var oImage = new Image;
					oImage.src = arguments[i][k];
				}
			}
 
			if (typeof(arguments[i]) == "string") {
				var oImage = new Image;
				oImage.src = arguments[i];
			}
		}
	}
}

Javascript unselectable text

admin — Thu, 18 Jun 2009 13:33:16 +0000

How to make text in an html page unselectable for the visitors? I don’t know for what reasons you may need this, but here is the code you want, read below.

Source code for webtoolkit.unselectable.js

/**
*
*  Unselectable text
*  http://www.webtoolkit.info/
*
**/
 
var Unselectable = {
 
	enable : function(e) {
		var e = e ? e : window.event;
 
		if (e.button != 1) {
			if (e.target) {
				var targer = e.target;
			} else if (e.srcElement) {
				var targer = e.srcElement;
			}
 
			var targetTag = targer.tagName.toLowerCase();
			if ((targetTag != "input") && (targetTag != "textarea")) {
				return false;
			}
		}
	},
 
	disable : function () {
		return true;
	}
 
}
 
if (typeof(document.onselectstart) != "undefined") {
	document.onselectstart = Unselectable.enable;
} else {
	document.onmousedown = Unselectable.enable;
	document.onmouseup = Unselectable.disable;
}

Javascript drag and drop

admin — Thu, 18 Jun 2009 13:14:05 +0000

Ever wanted to drag an element or image on your webpage? You can try using this very lightweight javascript drag handler. You can attach this drag handler to any relative or absolute positioned element.

First include the script at the top of your code (you can find the code in the source code section of this page). Do it in tag. After loading the script you can write your code to attach drag handler.

You can attach this drag handler to any number of elements on page and you will be able to drag them all. The most importaint thing is that these elements must be posisioned relatively or absolutely.

DEMO

Source code for webtoolkit.drag.js

/**
*
*  Crossbrowser Drag Handler
*  http://www.webtoolkit.info/
*
**/
 
var DragHandler = {
 
 
	// private property.
	_oElem : null,
 
 
	// public method. Attach drag handler to an element.
	attach : function(oElem) {
		oElem.onmousedown = DragHandler._dragBegin;
 
		// callbacks
		oElem.dragBegin = new Function();
		oElem.drag = new Function();
		oElem.dragEnd = new Function();
 
		return oElem;
	},
 
 
	// private method. Begin drag process.
	_dragBegin : function(e) {
		var oElem = DragHandler._oElem = this;
 
		if (isNaN(parseInt(oElem.style.left))) { oElem.style.left = '0px'; }
		if (isNaN(parseInt(oElem.style.top))) { oElem.style.top = '0px'; }
 
		var x = parseInt(oElem.style.left);
		var y = parseInt(oElem.style.top);
 
		e = e ? e : window.event;
		oElem.mouseX = e.clientX;
		oElem.mouseY = e.clientY;
 
		oElem.dragBegin(oElem, x, y);
 
		document.onmousemove = DragHandler._drag;
		document.onmouseup = DragHandler._dragEnd;
		return false;
	},
 
 
	// private method. Drag (move) element.
	_drag : function(e) {
		var oElem = DragHandler._oElem;
 
		var x = parseInt(oElem.style.left);
		var y = parseInt(oElem.style.top);
 
		e = e ? e : window.event;
		oElem.style.left = x + (e.clientX - oElem.mouseX) + 'px';
		oElem.style.top = y + (e.clientY - oElem.mouseY) + 'px';
 
		oElem.mouseX = e.clientX;
		oElem.mouseY = e.clientY;
 
		oElem.drag(oElem, x, y);
 
		return false;
	},
 
 
	// private method. Stop drag process.
	_dragEnd : function() {
		var oElem = DragHandler._oElem;
 
		var x = parseInt(oElem.style.left);
		var y = parseInt(oElem.style.top);
 
		oElem.dragEnd(oElem, x, y);
 
		document.onmousemove = null;
		document.onmouseup = null;
		DragHandler._oElem = null;
	}
 
}