jQuery disable/enable submit button

2018-05-30 13:03:41

I have this html:

<input type="text" name="textField" />
<input type="submit" value="send" />

How can I do something like this:

When the text field is empty the submit should be disabled (disabled="disabled").

When something is typed in the text field to remove the disabled attribute.

If the text field becomes empty again(the text is deleted) the submit button should be disabled again.

I tried something like this:

$(document).ready(function(){
    $('input[type="submit"]').attr('disabled','disabled');
    $('input[type="text"]').change(function(){
        if($(this).val != ''){
            $('input[type="submit"]').removeAttr('disabled');
        }
    });
});

... but it doesn't work. Any ideas? Thanks.

The problem is that the change event fires only when focus is moved away from the input (eg someone clicks off the input or tabs out of it). Try using keyup instead:

$(document).ready(function() {
     $(':input[type="submit"]').prop('disabled', true);
     $('input[type="text"]').keyup(function() {
        if($(this).val() != '') {
           $(':input[type="submit"]').prop('disabled', false);
        }
     });
 });

$(function() {
  $(":text").keypress(check_submit).each(function() {
    check_submit();
  });
});

function check_submit() {
  if ($(this).val().length == 0) {
    $(":submit").attr("disabled", true);
  } else {
    $(":submit").removeAttr("disabled");
  }
}

This question is 2 years old but it's still a good question and it was the first Google result ... but all of the existing answers recommend setting and removing the HTML attribute (removeAttr("disabled")) "disabled", which is not the right approach. There is a lot of confusion regarding attribute vs. property.

HTML

The "disabled" in <input type="button" disabled> in the markup is called a boolean attribute by the W3C.

HTML vs. DOM

Quote:

A property is in the DOM; an attribute is in the HTML that is parsed into the DOM.

https://stackoverflow.com/a/7572855/664132

JQuery

Nevertheless, the most important concept to remember about the checked attribute is that it does not correspond to the checked property. The attribute actually corresponds to the defaultChecked property and should be used only to set the initial value of the checkbox. The checked attribute value does not change with the state of the checkbox, while the checked property does. Therefore, the cross-browser-compatible way to determine if a checkbox is checked is to use the property...

Relevant:

Properties generally affect the dynamic state of a DOM element without changing the serialized HTML attribute. Examples include the value property of input elements, the disabled property of inputs and buttons, or the checked property of a checkbox. The .prop() method should be used to set disabled and checked instead of the .attr() method.

$( "input" ).prop( "disabled", false );

Summary

To [...] change DOM properties such as the [...] disabled state of form elements, use the .prop() method.

(http://api.jquery.com/attr/)

As for the disable on change part of the question: There is an event called "input", but browser support is limited and it's not a jQuery event, so jQuery won't make it work. The change event works reliably, but is fired when the element loses focus. So one might combine the two (some people also listen for keyup and paste).

Here's an untested piece of code to show what I mean:

$(document).ready(function() {
    var $submit = $('input[type="submit"]');
    $submit.prop('disabled', true);
    $('input[type="text"]').on('input change', function() { //'input change keyup paste'
        $submit.prop('disabled', !$(this).val().length);
    });
});

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