/*------------------------------------------------------------------------------------------------------
 -----------------------------------------------------------------------------------------------------
 
	Filename:		dcRollOver.js
	Programmers:	Keith Gaughan
					
	Copyright:		Released under BSD.
	Purpose:		Javascript Rollovers - changes image to active image or deactive image as mouse rolls over it
	Description:	
							1. Images must be in the form of:
								active	image	= "[name]_on.gif"
								disabled image	= "[name]_off.gif"
								Note: the extension (.gif) doesn't matter, .jpg/.png will also work.
									
							2. Include file into HTML page using:
								<script src="dcrollover.js"></script>
							
							3. To preload images use:
								PreloadImages("image1_on.gif","image1_off.gif",...);
							
							4. To activate/deactivate image use:
								<img name="[X]" src="[name]_off.gif" onMouseOver='RollOver("[X]")' onMouseOut='RollOver("[X]")'>
								replacing [X] and [name] with unique and appropriate names respectively.
							  
							5. New Option: To explicity set state rather than just toggle.
							   To force an image to ON state use RollOn("[X]")
							   To force the image to the OFF state, use RollOff("[X]")
							   e.g. <img name="[X]" src="[name]_off.gif" onMouseOver='RollOn("[X]")' onMouseOut='RollOff("[X]")'>

 	Change Log:		6 Mar 2002 - Peter Coppinger <peter@digital-crew.com>
					- Added RollOn() and RollOff() - need to explicity set state rather than just toggle.

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------------------------------------------------------------------------------------------------------*/
function PreloadImages()
{
    if (!document.images || arguments.length == 0)
        return;

    var tmp, j = arguments.length;

    for (var i = 0; i < j; ++i)
    {
        tmp = new Image();
        tmp.src = arguments[i];
    }
}

function RollOver(m)
{
    var s = document.images[m].src;

    if (s.lastIndexOf('_on.') >= 0)
        s = s.replace('_on.', '_off.');
    else if (s.lastIndexOf('_off.') >= 0)
        s = s.replace('_off.', '_on.');

    document.images[m].src = s;
}
function RollOn(m)
{
    var s = document.images[m].src;
    if (s.lastIndexOf('_off.') >= 0)
        s = s.replace('_off.', '_on.');
    document.images[m].src = s;
}
function RollOff(m)
{
    var s = document.images[m].src;
    if (s.lastIndexOf('_on.') >= 0)
        s = s.replace('_on.', '_off.');
    document.images[m].src = s;
}