Flash of white on page loads

OK…I’ve found the offending bit of code in JQueryUI 1.8.17.
It looks like they decided to do a test to see if your current version of jquery can handle fractions or not. This function creates a fake hidden body element and then tests for fraction support by manupulating this element.
Remove this function and the flash of white goes away (of course could now have an issue with old versions of jquery).

Here is the function in jquery 1.8.17 (beginning on line 10251)

// fraction support test (older versions of jQuery don't support fractions)
(function () {
	var body = document.getElementsByTagName( "body" )[ 0 ],
		div = document.createElement( "div" ),
		testElement, testElementParent, testElementStyle, offset, offsetTotal;

	//Create a "fake body" for testing based on method used in jQuery.support
	testElement = document.createElement( body ? "div" : "body" );
	testElementStyle = {
		visibility: "hidden",
		width: 0,
		height: 0,
		border: 0,
		margin: 0,
		background: "none"
	};
	if ( body ) {
		jQuery.extend( testElementStyle, {
			position: "absolute",
			left: "-1000px",
			top: "-1000px"
		});
	}
	for ( var i in testElementStyle ) {
		testElement.style[ i ] = testElementStyle[ i ];
	}
	testElement.appendChild( div );
	testElementParent = body || document.documentElement;
	testElementParent.insertBefore( testElement, testElementParent.firstChild );

	div.style.cssText = "position: absolute; left: 10.7432222px; top: 10.432325px; height: 30px; width: 201px;";

	offset = $( div ).offset( function( _, offset ) {
		return offset;
	}).offset();

	testElement.innerHTML = "";
	testElementParent.removeChild( testElement );

	offsetTotal = offset.top + offset.left + ( body ? 2000 : 0 );
	support.fractions = offsetTotal > 21 && offsetTotal < 22;
})();

This same function (with minor changes) has existed in ALL versions of jqueryUI up to the current 1.10.3 beginning on line 12474

// fraction support test
(function () {
	var testElement, testElementParent, testElementStyle, offsetLeft, i,
		body = document.getElementsByTagName( "body" )[ 0 ],
		div = document.createElement( "div" );

	//Create a "fake body" for testing based on method used in jQuery.support
	testElement = document.createElement( body ? "div" : "body" );
	testElementStyle = {
		visibility: "hidden",
		width: 0,
		height: 0,
		border: 0,
		margin: 0,
		background: "none"
	};
	if ( body ) {
		$.extend( testElementStyle, {
			position: "absolute",
			left: "-1000px",
			top: "-1000px"
		});
	}
	for ( i in testElementStyle ) {
		testElement.style[ i ] = testElementStyle[ i ];
	}
	testElement.appendChild( div );
	testElementParent = body || document.documentElement;
	testElementParent.insertBefore( testElement, testElementParent.firstChild );

	div.style.cssText = "position: absolute; left: 10.7432222px;";

	offsetLeft = $( div ).offset().left;
	$.support.offsetFractions = offsetLeft > 10 && offsetLeft < 11;

	testElement.innerHTML = "";
	testElementParent.removeChild( testElement );
})();

I’m going to file this with jquery and see what they have to say.