if (document.images) {

       	    img1on = new Image();
            img1on.src = "images/idahoPTSlogoOn.jpg";
            img2on = new Image();
            img2on.src = "images/montanaPTSlogoOn.jpg";
            img3on = new Image();
            img3on.src = "images/headlineIdahoRO.jpg";
            img4on = new Image();
            img4on.src = "images/headlineMontanaRO.jpg";
            
            img1off = new Image(); 								
            img1off.src = "images/idahoPTSlogo.jpg";
            img2off = new Image(); 								
            img2off.src = "images/montanaPTSlogo.jpg";
            img3off = new Image(); 								
            img3off.src = "images/headlineIdaho.jpg";
            img4off = new Image(); 								
            img4off.src = "images/headlineMontana.jpg";
            
         
           }

function imgOn(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "on.src");
        }
}

function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off.src");
        }
}