jQuery - Why does $('form').get(0).submit(

问题:

Suppose I've created the following handler (callback) for a form:

$('form').submit(function (event) {
   event.preventDefault();
   alert('form submitted');
});

Why does calling $('form').get(0).submit not call the submit handler? The form just gets directly submitted.

回答1:

.get(0) returns the native js DOM element ( Same as $('form')[0] ) and then you are triggering the submit event directly.

if you are trying to get the first Element use .eq(0) and trigger the submit jQuery style using .submit().

Summary:

• $('selector')[0] ~ returns the native js DOM element
• .get(0) ~ Same as [0].
• .eq(0) ~ returns the first element as a jQuery object .

More:

• Attach to submit event (jQuery): $('form.selector').submit(function (e) { });
• Trigger Submit (jQuery): $('form.selector').submit(); OR $('form.selector').trigger('submit');
• Trigger Submit on the first element: $('form').eq(0).submit();

Demo: jsFiddle

I hope its what you need.

Demo jQuery:

$('form').submit(function (event) {
    event.preventDefault(); // Will prevent the native handler from firing.
    alert('form submitted :' + $(this).attr("id"));
});

//change the `.eq(index)` to 1 to trigger the submit on the second form:  
$('form').eq(0).submit(); // Same as: $('form').eq(0).trigger("submit");

Demo HTML:

<form id="form1"></form>
<form id="form2"></form>