var realImageW = 0;
var realImageH = 0;


function fitImageToPage()
{
	if ( document.getElementById )
	{
		var theImage = document.getElementById('image');
		var reference = document.getElementById('reference_div');
	
		if ( realImageW == 0 && realImageH == 0 )
		{
			realImageW = theImage.width;
			realImageH = theImage.height;
		}
		
		var referenceWidth = reference.clientWidth;
		
		if ( realImageW > referenceWidth )
		{
			theImage.width = referenceWidth;
			theImage.height = (realImageH * referenceWidth / realImageW);
		}
		else
		{
			theImage.width = realImageW;
			theImage.height = realImageH;
		}
	}
}

if ( window.addEventListener )
{
	// DOM
	window.addEventListener( 'load', fitImageToPage, false );
	window.addEventListener( 'resize', fitImageToPage, false );
}
else if ( window.attachEvent )
{
	// IE
	window.attachEvent( 'onload', fitImageToPage );
	window.attachEvent( 'onresize', fitImageToPage );
}