prevent submitting form twice
There is a simple method of preventing multiple submits not only from one button but all buttons on page. For example someone may click OK button and then Cancel button - it is not double click on one button so previous solutions wont help.
1) put hidden field on page that will tell us if submit has been already made
<asp:HiddenField ID="HFSubmitForm" runat="server" Value="0" />
2) create javascript function that will check the value of hidden field and return false if submit has been made
<script language="javascript" type="text/javascript">
function checkSubmit()
{
// support clientside validation - if page is not valid framework wont fire
// postback
if ((typeof(Page_IsValid )!="undefined")&&(Page_IsValid == false))
{
document.getElementById("<%=HFSubmitForm.ClientID%>").value = 0;
return true;
}
// if postback - return false
if (document.getElementById("<%=HFSubmitForm.ClientID%>").value==1)
return false;
else
{
// mark that submit is to be done and return true
document.getElementById("<%=HFSubmitForm.ClientID%>").value = 1;
return true;
}
}
</script>
3) in every button on page add the following at begin of "OnClientClick" event:
if (checkSubmit()==false) {alert('form already submitted!'); return false;}
4) on Page_Load() in code behind file add the following line:
HFSubmitForm.Value = "0";
Thats it! It should work with popular browsers (opera, firefox, ie) and with clientside validation
.