var previousItem = null;
var currentItem = null;

function RollOver(sID){
    
    currentItem = document.getElementById(sID);
    
    if(previousItem){
        previousItem.src = previousItem.src.replace('_Over','')
    }
    
    currentItem.src = currentItem.src.replace('.jpg','') + '_Over.jpg'

    previousItem = currentItem
}

function RollOut(){

    if(previousItem){
        previousItem.src = previousItem.src.replace('_Over','')
    }
    
}