function ChangeColor(index)
{
	for(i=0;i < btnImgArr.length; i++)
	{
	if (document.getElementById(btnImgArr[i])!=null)
		{
		if(i==index)
		{
		
			var val = document.getElementById(btnImgArr[i]).src;
			var newstring = val.replace("_off","_on");
			document.getElementById(btnImgArr[i]).src = newstring;
		}
		else
		{
			var val = document.getElementById(btnImgArr[i]).src;
			var newstring = val.replace("_on","_off");
			document.getElementById(btnImgArr[i]).src = newstring;
			
		}
		}
	}	
}