Schepp / box-sizing-polyfill

/**
* CSS-JS-BOOSTER
* 
* A polyfill for box-sizing: border-box for IE6 & IE7.
* 
* JScript
* 
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published 
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* 
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
* 
* See <http://www.gnu.org/licenses/lgpl-3.0.txt>
* 
* @category  JScript 
* @package   box-sizing-polyfill
* @author    Christian Schepp Schaefer <schaepp@gmx.de> <http://twitter.com/derSchepp>
* @copyright 2010 Christian Schepp Schaefer
* @license   http://www.gnu.org/copyleft/lesser.html The GNU LESSER GENERAL PUBLIC LICENSE, Version 3.0
* @link      http://github.com/Schepp/box-sizing-polyfill 
*
* PREFACE:
*
* This box-sizing polyfill is based on previous work done by Erik Arvidsson, 
* which he published in 2002 on http://webfx.eae.net/dhtml/boxsizing/boxsizing.html.
*
* USAGE:
* 	
* Add the behavior/HTC after every `box-sizing: border-box;` that you assign:
* 
* box-sizing: border-box;
* *behavior: url(/scripts/boxsizing.htc);`
* 
* If you prefix the `behavior` property with a star, like seen above, it will only be seen by 
* IE6 & IE7, not by IE8+ (it's a hack) which is better for the performance on those newer browsers.
*
* The URL to the HTC file must be relative to your HTML(!) document, not relative to your CSS.
* That's why I'd advise you to use absolute paths like in the example.
*
*/
<component lightWeight="true">
<attach event="onpropertychange" onevent="checkPropertyChange()" />
<attach event="ondetach" onevent="restore()" />
<attach event="onresize" for="window" onevent="restore();init()" />
<script type="text/javascript">
//<![CDATA[

var viewportwidth = (typeof window.innerWidth != 'undefined' ? window.innerWidth : element.document.documentElement.clientWidth);
// Shortcut for the document object
var doc = element.document;

/*
* init gets called once at the start and then never again, 
* triggers box-sizing calculations and updates width and height
*/
function init(){
	updateBorderBoxWidth();
	updateBorderBoxHeight();
}

/*
* restore gets called when the behavior is being detached (see event binding at the top),
* resets everything like it was before applying the behavior
*/
function restore(){
	element.runtimeStyle.width = "";
	element.runtimeStyle.height = "";
}

/*
* checkPropertyChange gets called as soon as an element property changes 
* (see event binding at the top), it then checks if any property influencing its 
* dimensions was changed and if yes recalculates width and height 
*/
function checkPropertyChange(){
	var pn = event.propertyName;
	var undef;
	if(pn == "style.boxSizing" && element.style.boxSizing == ""){
		element.style.removeAttribute("boxSizing");
		element.runtimeStyle.boxSizing = undef;
	}
	switch (pn){
		case "style.width":
		case "style.borderLeftWidth":
		case "style.borderLeftStyle":
		case "style.borderRightWidth":
		case "style.borderRightStyle":
		case "style.paddingLeft":
		case "style.paddingRight":
			updateBorderBoxWidth();
		break;

		case "style.height":
		case "style.borderTopWidth":
		case "style.borderTopStyle":
		case "style.borderBottomWidth":
		case "style.borderBottomStyle":
		case "style.paddingTop":
		case "style.paddingBottom":
			updateBorderBoxHeight();
		break;

		case "className":
		case "style.boxSizing":
			updateBorderBoxWidth();
			updateBorderBoxHeight();
		break;
	}

}

/* 
 * Helper function, taken from Dean Edward's IE7 framework,
 * added by Schepp on 12.06.2010.
 * http://code.google.com/p/ie7-js/
 *
 * Allows us to convert from relative to pixel-values.
 */
function getPixelValue(value){
	var PIXEL = /^\d+(px)?$/i;
	if (PIXEL.test(value)) return parseInt(value);
	var style = element.style.left;
	var runtimeStyle = element.runtimeStyle.left;
	element.runtimeStyle.left = element.currentStyle.left;
	element.style.left = value || 0;
	value = parseInt(element.style.pixelLeft);
	element.style.left = style;
	element.runtimeStyle.left = runtimeStyle;

	return value;
}

function getPixelWidth(object, value){
	// For Pixel Values
	var PIXEL = /^\d+(px)?$/i;
	if (PIXEL.test(value)) return parseInt(value);

	// For Percentage Values
	var PERCENT = /^[\d\.]+%$/i;
	if (PERCENT.test(value)){
		try{
			parentWidth = getPixelWidth(object.parentElement,(object.parentElement.currentStyle.width != "auto" ? object.parentElement.currentStyle.width : "100%"));
			value = (parseFloat(value) / 100) * parentWidth;
		}
		catch(e){
			value = (parseFloat(value) / 100) * element.document.documentElement.clientWidth;
		}
		return parseInt(value);
	}

	// For EM Values
	var style = object.style.left;
	var runtimeStyle = object.runtimeStyle.left;
	object.runtimeStyle.left = object.currentStyle.left;
	object.style.left = value || 0;
	value = parseInt(object.style.pixelLeft);
	object.style.left = style;
	object.runtimeStyle.left = runtimeStyle;

	return value;
}


/*
 * getBorderWidth & friends
 * Border width getters
 */
function getBorderWidth(sSide){
	if(element.currentStyle["border" + sSide + "Style"] == "none"){
		return 0;
	}
	var n = getPixelValue(element.currentStyle["border" + sSide + "Width"]);
	return n || 0;
}
function getBorderLeftWidth() { return getBorderWidth("Left"); }
function getBorderRightWidth() { return getBorderWidth("Right"); }
function getBorderTopWidth() { return getBorderWidth("Top"); }
function getBorderBottomWidth() { return getBorderWidth("Bottom"); }


/*
 * getPadding & friends
 * Padding width getters
 */
function getPadding(sSide) {
	var n = getPixelValue(element.currentStyle["padding" + sSide]);
	return n || 0;
}
function getPaddingLeft() { return getPadding("Left"); }
function getPaddingRight() { return getPadding("Right"); }
function getPaddingTop() { return getPadding("Top"); }
function getPaddingBottom() { return getPadding("Bottom"); }



/*
 * getBoxSizing
 * Get the box-sizing value for the current element
 */
function getBoxSizing(){
	var s = element.style;
	var cs = element.currentStyle
	if(typeof s.boxSizing != "undefined" && s.boxSizing != ""){
		return s.boxSizing;
	}
	if(typeof s["box-sizing"] != "undefined" && s["box-sizing"] != ""){
		return s["box-sizing"];
	}
	if(typeof cs.boxSizing != "undefined" && cs.boxSizing != ""){
		return cs.boxSizing;
	}
	if(typeof cs["box-sizing"] != "undefined" && cs["box-sizing"] != ""){
		return cs["box-sizing"];
	}
	return getDocumentBoxSizing();
}


/*
 * getDocumentBoxSizing
 * Get the default document box sizing (check for quirks mode)
 */
function getDocumentBoxSizing(){
	if(doc.compatMode == null || doc.compatMode == "BackCompat"){
		return "border-box";
	}
	return "content-box"
}


/*
 * setBorderBoxWidth & friends
 * Width and height setters
 */
function setBorderBoxWidth(n){
	element.runtimeStyle.width = Math.max(0, n - getBorderLeftWidth() -
		getPaddingLeft() - getPaddingRight() - getBorderRightWidth()) + "px";
}
function setBorderBoxHeight(n){
	element.runtimeStyle.height = Math.max(0, n - getBorderTopWidth() -
		getPaddingTop() - getPaddingBottom() - getBorderBottomWidth()) + "px";
}
function setContentBoxWidth(n){
	element.runtimeStyle.width = Math.max(0, n + getBorderLeftWidth() +
		getPaddingLeft() + getPaddingRight() + getBorderRightWidth()) + "px";
}
function setContentBoxHeight(n){
	element.runtimeStyle.height = Math.max(0, n + getBorderTopWidth() +
		getPaddingTop() + getPaddingBottom() + getBorderBottomWidth()) + "px";
}


/*
 * updateBorderBoxWidth & updateBorderBoxHeight
 * 
 */
function updateBorderBoxWidth() {
	if(getDocumentBoxSizing() == getBoxSizing()){
		return;
	}
	var csw = element.currentStyle.width;
	if(csw != "auto"){
		csw = getPixelWidth(element,csw);
		if(getBoxSizing() == "border-box"){
			setBorderBoxWidth(parseInt(csw));
		}
		else{
			setContentBoxWidth(parseInt(csw));
		}
	}
}

function updateBorderBoxHeight() {
	if(getDocumentBoxSizing() == getBoxSizing()){
		return;
	}
	var csh = element.currentStyle.height;
	if(csh != "auto"){
		csh = getPixelValue(csh);
		if(getBoxSizing() == "border-box"){
			setBorderBoxHeight(parseInt(csh));
		}
		else{
			setContentBoxHeight(parseInt(csh));
		}
	}
}


// Run the calculations
init();

//]]>
</script>
</component>