Question

How would I add additional functionality to the jQuery validation submitHandler that is set in another script? I cannot modify the source JavaScript that is defining the submitHandler in the first place. Instead, I need to add some additional functionality to it from a subsequent script that runs. Here is some scaled-down pseudo-code for the .js file that is defining the submitHandler in the first place–which I cannot directly modify:

$("#frmReg").validate({
    invalidHandler: function(e, validator) { //code here ... not relevant },
    submitHandler: function() {
        window.onbeforeunload = null;
        $('#myForm')[0].submit();             
    },
    rules: { firstname: { required: true } },
    messages: { firstname: { required: 'First name is required' } }
});

Essentially, I want to bind a second function to the existing submitHander.

Answer 1

I glanced over the source and I think this should work:

var validatorInstance = $("#frmReg").validate(), //Call this AFTER the initial registration,
    submitHandler = validatorInstance.settings.submitHandler;

validatorInstance.settings.submitHandler = function(){
    //Do your custom stuff here
    console.log(true);
    return submitHandler.apply(this,arguments); //forward to the old handler
};