function kve3() {
var a = document.forms["calc3"].elements["a"].value;
var b = document.forms["calc3"].elements["b"].value;
var result = Math.round(((a-b) *688)*100)/100; 
var result = '$' + result.toFixed(2);
 
document.forms["calc3"].elements["result"].value = result;
return false;
}