.val()

The .val() method is primarily used to get the values of form elements such as input, select and textarea. When called on an empty collection, it returns undefined.

When the first element in the collection is a select-multiple (i.e., a select element with the multiple attribute set), .val() returns an array containing the value of each selected option. As of jQuery 3.0, if no options are selected, it returns an empty array; prior to jQuery 3.0, it returns null.

For selects, checkboxes and radio buttons, you can also use the :selected and :checked selectors to get at values. For example:

 
// Get the value from a dropdown select
$( "select.foo option:selected").val();
 
// Get the value from a dropdown select even easier
$( "select.foo" ).val();
 
// Get the value from a checked checkbox
$( "input:checkbox:checked" ).val();
 
// Get the value from a set of radio buttons
$( "input:radio[name=bar]:checked" ).val();

$.valHooks.textarea = {
  get: function( elem ) {
    return elem.value.replace( /\r?\n/g, "\r\n" );
  }
};

This method is typically used to set the values of form fields.

val() allows you to pass an array of element values. This is useful when working on a jQuery object containing elements like <input type="checkbox">, <input type="radio">, and <option>s inside of a <select>. In this case, the inputs and the options having a value that matches one of the elements of the array will be checked or selected while those having a value that doesn't match one of the elements of the array will be unchecked or unselected, depending on the type. In the case of <input type="radio">s that are part of a radio group and <select>s, any previously selected element will be deselected.

Setting values using this method (or using the native value property) does not cause the dispatch of the change event. For this reason, the relevant event handlers will not be executed. If you want to execute them, you should call .trigger( "change" ) after setting the value.

The .val() method allows setting the value by passing in a function. As of jQuery 1.4, the function is passed two arguments, the current element's index and its current value:

$( "input:text.items" ).val(function( index, value ) {
  return value + " " + this.className;
});

This example appends the string " items" to the text inputs' values.