javascript swap images on mouseover

JavaScript
function rollover(my_image)
		{
	
			my_image.src = 'images/costAnalysisBtn2.png';
	
		}
function mouseaway(my_image)
		{
	
			my_image.src = "images/costAnalysisBtn1.png";
	
		}
onmouseover="rollover(this)" onmouseout="mouseaway(this)"
Source

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