Can help me check this code

function calculate() {
var n1=parseInt(firstnum.value);
var n2=parseInt(secondnum.value);
result.value=n1+n2;
}
function reset() {
firstnum.value="";
secondnum.value=&;quot;"; <---&;quot 換成 &quot
result.value="";
}
function check(field) {
if (isNaN=(field.value)){
alert("Invalid please try again!");
return false;
}
else
return true;
}

2007-07-27 13:10:26 補充：
打唔到，係咁將我D字 變左 "

I believe that the problem is the script cannot detect what "firstnum","secondnum", "result" is.

First, you should add id="firstnum" into the tag where you wish to be firstnum

Then, in the script, change firstnum into:

document.getElementById("firstnum")

The problem should be solved.