Aborting an Ajax request if confirmation dialog is "Cancel"

I'd like to have a <f:ajax> component that would display a confirmation dialog and then do the action tag if OK was selected or abort if Cancel was selected. I thought this would work, but it doesn't (The ajax part runs no matter what I select in the confirmation):

<f:ajax render="some_div">
<h:commandButton value="A Hazardous Button!"
  onclick="show_confirm()" action="#{bean.doSomething}开发者_运维知识库" />
</f:ajax>

-

function show_confirm()
{
    var r=confirm("Are you sure you want to do this? This is totally hazardous!");
    if (r==true)
    {
      return true;
    }
    else
    {
      return false;
    }
}

Any idea why?

Firstly you need to add the return keyword to your onclick handler... try changing onclick="show_confirm()" to onclick="return show_confirm()"

secondly, you can simplify your function to:

function show_confirm()
{
    return confirm("Are you sure you want to do this? This is totally hazardous!");
}

For JSF ajax you can do with following way.

<script>
function show_confirm()
{
  return confirm("Are you sure you want to do this? This is totally hazardous!");
}
</script>

<h:commandButton value="A Hazardous Button!" onclick="return show_confirm()">
 <f:ajax listener=#{bean.doSomething}"/>
</h:commandButton>