function alterTable(){
var table = document.getElementById("results");
var rows = table.getElementsByTagName("tr");
for (i=0; i < rows.length; i++) {
    var oldClass = null;
    rows[i].onmouseover = function() { 
        oldClass = this.className;
        this.className='over' 
    };
    rows[i].onmouseout = function() { 
        this.className=oldClass 
    };
}
}