Form clears after alert

[bezaman]

I have three buttons included in my form. I have a javascript onclick event for one of the submit buttons. Here is the javascript associated with the onclick event:

function chkSave(){
if(document.form1.txtjobnum.value == "")
{
window.alert("please enter a job number");
document.form1.txtjobnum.focus();
return false;
}
}

The alert box works correctly but whenever I click on OK in the alert box my all the data in my form is cleared. Can anybody explain why this is happening?

[Hack]

Any refreshing going on that isn't being shown?

[bezaman]

No refreshing. I thought return false was the solution but it doesn't work.

[Hack]

If you click on Cancel on the Alert button, does the same thing happen?

[bezaman]

There is no choice for a cancel, there is just an OK button.