asp.net - Javascript Confirmation for CheckBox on Unchecked Click -

i have checkbox auto post when changed.

the auto post works fine both (checked , unchecked), want popup dialog box confirm before each event takes place.

so far popup box works when checkbox checked.

but not popup confirmation dialog box, when checkbox unchecked.

question: how popup dialog box uncheck event using client side code (only)

<asp:checkbox id="currentcheckbox" runat="server" autopostback="true" checked='<%# bind("bdvalue") %>' oncheckedchanged="sharedfunctionforthischeckbox_checkedchanged" onclick="checkboxconfirmclick(this);" />   <script type="text/javascript">             function checkboxconfirmclick(elementref) {         if (elementref.checked) {             if (window.confirm('are sure?') == false)                 elementref.checked = false;         }     } </script> 

if current method works can simplify to

function checkboxconfirmclick(elementref) {     if (!window.confirm('are sure?')) { // if not sure         elementref.checked = !elementref.checked; // toggle     } } 

however, best pass event through handler instead (i.e. e) , do

function checkboxconfirmclick(e) {     if (!window.confirm('are sure?')) { // if not sure         e.preventdefault(); // kill click     } } 

you may want e.stoppropagation() if have other handlers attached higher don't want event reach.

• event.preventdefault
• event.stoppropagation