ns4 = (document.layers) ? true : false
ie4 = (document.all) ? true : false
ng5 = (document.getElementById) ? true : false 

function ClearText(n) {
    if (ng5) document.getElementById(n).value = "";
    else if (ns4) document.layers[n].value = "";
    else if (ie4) document.all[n].value = "";    
}