Question

I have function that submitted two forms at once. And last (the second) post method does not take effect without alert().

Could you please show me my mistake.

  function formFunction() {
        ...
        $.post($("#form1").attr("action"), $("#form1").serialize() );
        $.post($("#form2").attr("action"), $("#form2").serialize() );

        //alert('done');
}

UPD

this is how function is calling

<form id="form0" name="form0" onsubmit="formFunction()">
    <input id="mainFormValue" type="text">

Answer 1

The reason why it is failing is you are not cancelling the original form submission. That means the page is posting back to the server when you click the button. What you need to do is prevent that origial form submission from completing.

If you are adding the event handler with jQuery, you can use preventDefault() to cancel the form submission.

function formFunction(e) {
     e.preventDefault();
     $.post($("#form1").attr("action"), $("#form1").serialize() );
     $.post($("#form2").attr("action"), $("#form2").serialize() );
}

Change the form submission to unobtrusive JavaScript to get the correct event object set by jQuery.

$("#form0").submit(formFunction);

The other solutions is add a return false to the submisison. Just ignore the preventDefault line I suggested above. [bad idea, but will work]

<form id="form0" name="form0" onsubmit="formFunction(); return false">