jquery/src/support.js

(function( jQuery ) {

(function() {

	jQuery.support = {};

	var root = document.documentElement,
		script = document.createElement("script"),
		div = document.createElement("div"),
		id = "script" + jQuery.now();

	div.style.display = "none";
	div.innerHTML = "   <link/><table></table><a href='/a' style='color:red;float:left;opacity:.55;'>a</a><input type='checkbox'/>";

	var all = div.getElementsByTagName("*"),
		a = div.getElementsByTagName("a")[0],
		select = document.createElement("select"),
		opt = select.appendChild( document.createElement("option") );

	// Can't get basic test support
	if ( !all || !all.length || !a ) {
		return;
	}

	jQuery.support = {
		// IE strips leading whitespace when .innerHTML is used
		leadingWhitespace: div.firstChild.nodeType === 3,

		// Make sure that tbody elements aren't automatically inserted
		// IE will insert them into empty tables
		tbody: !div.getElementsByTagName("tbody").length,

		// Make sure that link elements get serialized correctly by innerHTML
		// This requires a wrapper element in IE
		htmlSerialize: !!div.getElementsByTagName("link").length,

		// Get the style information from getAttribute
		// (IE uses .cssText insted)
		style: /red/.test( a.getAttribute("style") ),

		// Make sure that URLs aren't manipulated
		// (IE normalizes it by default)
		hrefNormalized: a.getAttribute("href") === "/a",

		// Make sure that element opacity exists
		// (IE uses filter instead)
		// Use a regex to work around a WebKit issue. See #5145
		opacity: /^0.55$/.test( a.style.opacity ),

		// Verify style float existence
		// (IE uses styleFloat instead of cssFloat)
		cssFloat: !!a.style.cssFloat,

		// Make sure that if no value is specified for a checkbox
		// that it defaults to "on".
		// (WebKit defaults to "" instead)
		checkOn: div.getElementsByTagName("input")[0].value === "on",

		// Make sure that a selected-by-default option has a working selected property.
		// (WebKit defaults to false instead of true, IE too, if it's in an optgroup)
		optSelected: opt.selected,

		// Will be defined later
		deleteExpando: true,
		optDisabled: false,
		checkClone: false,
		scriptEval: false,
		noCloneEvent: true,
		boxModel: null,
		inlineBlockNeedsLayout: false,
		shrinkWrapBlocks: false,
		reliableHiddenOffsets: true
	};

	// Make sure that the options inside disabled selects aren't marked as disabled
	// (WebKit marks them as diabled)
	select.disabled = true;
	jQuery.support.optDisabled = !opt.disabled;

	script.type = "text/javascript";
	try {
		script.appendChild( document.createTextNode( "window." + id + "=1;" ) );
	} catch(e) {}

	root.insertBefore( script, root.firstChild );

	// Make sure that the execution of code works by injecting a script
	// tag with appendChild/createTextNode
	// (IE doesn't support this, fails, and uses .text instead)
	if ( window[ id ] ) {
		jQuery.support.scriptEval = true;
		delete window[ id ];
	}

	// Test to see if it's possible to delete an expando from an element
	// Fails in Internet Explorer
	try {
		delete script.test;

	} catch(e) {
		jQuery.support.deleteExpando = false;
	}

	root.removeChild( script );

	if ( div.attachEvent && div.fireEvent ) {
		div.attachEvent("onclick", function click() {
			// Cloning a node shouldn't copy over any
			// bound event handlers (IE does this)
			jQuery.support.noCloneEvent = false;
			div.detachEvent("onclick", click);
		});
		div.cloneNode(true).fireEvent("onclick");
	}

	div = document.createElement("div");
	div.innerHTML = "<input type='radio' name='radiotest' checked='checked'/>";

	var fragment = document.createDocumentFragment();
	fragment.appendChild( div.firstChild );

	// WebKit doesn't clone checked state correctly in fragments
	jQuery.support.checkClone = fragment.cloneNode(true).cloneNode(true).lastChild.checked;

	// Figure out if the W3C box model works as expected
	// document.body must exist before we can do this
	jQuery(function() {
		var div = document.createElement("div");
		div.style.width = div.style.paddingLeft = "1px";

		document.body.appendChild( div );
		jQuery.boxModel = jQuery.support.boxModel = div.offsetWidth === 2;

		if ( "zoom" in div.style ) {
			// Check if natively block-level elements act like inline-block
			// elements when setting their display to 'inline' and giving
			// them layout
			// (IE < 8 does this)
			div.style.display = "inline";
			div.style.zoom = 1;
			jQuery.support.inlineBlockNeedsLayout = div.offsetWidth === 2;

			// Check if elements with layout shrink-wrap their children
			// (IE 6 does this)
			div.style.display = "";
			div.innerHTML = "<div style='width:4px;'></div>";
			jQuery.support.shrinkWrapBlocks = div.offsetWidth !== 2;
		}

		div.innerHTML = "<table><tr><td style='padding:0;border:0;display:none'></td><td>t</td></tr></table>";
		var tds = div.getElementsByTagName("td");

		// Check if table cells still have offsetWidth/Height when they are set
		// to display:none and there are still other visible table cells in a
		// table row; if so, offsetWidth/Height are not reliable for use when
		// determining if an element has been hidden directly using
		// display:none (it is still safe to use offsets if a parent element is
		// hidden; don safety goggles and see bug #4512 for more information).
		// (only IE 8 fails this test)
		jQuery.support.reliableHiddenOffsets = tds[0].offsetHeight === 0;

		tds[0].style.display = "";
		tds[1].style.display = "none";

		// Check if empty table cells still have offsetWidth/Height
		// (IE < 8 fail this test)
		jQuery.support.reliableHiddenOffsets = jQuery.support.reliableHiddenOffsets && tds[0].offsetHeight === 0;
		div.innerHTML = "";

		document.body.removeChild( div ).style.display = "none";
		div = tds = null;
	});

	// Technique from Juriy Zaytsev
	// http://thinkweb2.com/projects/prototype/detecting-event-support-without-browser-sniffing/
	var eventSupported = function( eventName ) {
		var el = document.createElement("div");
		eventName = "on" + eventName;

		var isSupported = (eventName in el);
		if ( !isSupported ) {
			el.setAttribute(eventName, "return;");
			isSupported = typeof el[eventName] === "function";
		}
		el = null;

		return isSupported;
	};

	jQuery.support.submitBubbles = eventSupported("submit");
	jQuery.support.changeBubbles = eventSupported("change");

	// release memory in IE
	root = script = div = all = a = null;
})();
})( jQuery );