How to get the containing form of an input?

Every input has a form property which points to the form the input belongs to, so simply:

function doSomething(element) {
  var form = element.form;
}

Native DOM elements that are inputs also have a form attribute that points to the form they belong to:

var form = element.form;
alert($(form).attr('name'));

According to w3schools, the .form property of input fields is supported by IE 4.0+, Firefox 1.0+, Opera 9.0+, which is even more browsers that jQuery guarantees, so you should stick to this.

If this were a different type of element (not an <input>), you could find the closest parent with closest:

var $form = $(element).closest('form');
alert($form.attr('name'));

Also, see this MDN link on the form property of HTMLInputElement:

• https://developer.mozilla.org/en/DOM/HTMLInputElement#Properties

I use a bit of jQuery and old style javascript - less code

$($(this)[0].form) 

This is a complete reference to the form containing the element

Using jQuery:

function doSomething(element) {
    var form = $(element).closest("form").get().
    //do something with the form.
}