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?