如何处理 jQuery 中的表单更改？

小开

$('form :input').change(function() {
// Something has changed
});

小开

First, I'd add a hidden input to your form to track the state of the form. Then, I'd use this jQuery snippet to set the value of the hidden input when something on the form changes:

    $("form")
.find("input")
.change(function(){
if ($("#hdnFormChanged").val() == "no")
{
$("#hdnFormChanged").val("yes");
}
});

When your button is clicked, you can check the state of your hidden input:

$("#Button").click(function(){
if($("#hdnFormChanged").val() == "yes")
{
// handler code here...
}
});

小开

Looking at the updated question try something like

$('input, textarea, select').each(function(){
$(this).data("val", $(this).val());
});
$('#button').click(function() {
$('input, textarea, select').each(function(){
if($(this).data("val")!==$(this).val()) alert("Things Changed");
});
});

For the original question use something like

$('input').change(function() {
alert("Things have changed!");
});

小开

You can use multiple selectors to attach a callback to the change event for any form element.

$("input, select").change(function(){
// Something changed
});

EDIT

Since you mentioned you only need this for a click, you can simply modify my original code to this:

$("input, select").click(function(){
// A form element was clicked
});

EDIT #2

Ok, you can set a global that is set once something has been changed like this:

var FORM_HAS_CHANGED = false;


$('#mybutton').click(function() {
if (FORM_HAS_CHANGED) {
// The form has changed
}
});


$("input, select").change(function(){
FORM_HAS_CHANGED = true;
});

小开

最佳答案

You can do this:

$("form :input").change(function() {
$(this).closest('form').data('changed', true);
});
$('#mybutton').click(function() {
if($(this).closest('form').data('changed')) {
//do something
}
});

This rigs a change event handler to inputs in the form, if any of them change it uses .data() to set a changed value to true, then we just check for that value on the click, this assumes that #mybutton is inside the form (if not just replace $(this).closest('form') with $('#myForm')), but you could make it even more generic, like this:

$('.checkChangedbutton').click(function() {
if($(this).closest('form').data('changed')) {
//do something
}
});

References: Updated

According to jQuery this is a filter to select all form controls.

http://api.jquery.com/input-selector/

The :input selector basically selects all form controls.

小开

You need jQuery Form Observe plugin. That's what you are looking for.

小开

If you want to check if the form data, as it is going to be sent to the server, have changed, you can serialize the form data on page load and compare it to the current form data:

$(function() {


var form_original_data = $("#myform").serialize();


$("#mybutton").click(function() {
if ($("#myform").serialize() != form_original_data) {
// Something changed
}
});


});

小开

A real time and simple solution:

$('form').on('keyup change paste', 'input, select, textarea', function(){
console.log('Form changed!');
});

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Extending Udi's answer, this only checks on form submission, not on every input change.

$(document).ready( function () {
var form_data = $('#myform').serialize();
$('#myform').submit(function () {
if ( form_data == $(this).serialize() ) {
alert('no change');
} else {
alert('change');
}
});
});

小开

Here is an elegant solution.

There is hidden property for each input element on the form that you can use to determine whether or not the value was changed. Each type of input has it's own property name. For example

for text/textarea it's defaultValue
for select it's defaultSelect
for checkbox/radio it's defaultChecked

Here is the example.

function bindFormChange($form) {


function touchButtons() {
var
changed_objects = [],
$observable_buttons = $form.find('input[type="submit"], button[type="submit"], button[data-object="reset-form"]');


changed_objects = $('input:text, input:checkbox, input:radio, textarea, select', $form).map(function () {
var
$input = $(this),
changed = false;


if ($input.is('input:text') || $input.is('textarea') ) {
changed = (($input).prop('defaultValue') != $input.val());
}
if (!changed && $input.is('select') ) {
changed = !$('option:selected', $input).prop('defaultSelected');
}
if (!changed && $input.is('input:checkbox') || $input.is('input:radio') ) {
changed = (($input).prop('defaultChecked') != $input.is(':checked'));
}
if (changed) {
return $input.attr('id');
}


}).toArray();


if (changed_objects.length) {
$observable_buttons.removeAttr('disabled')
} else {
$observable_buttons.attr('disabled', 'disabled');
}
};
touchButtons();


$('input, textarea, select', $form).each(function () {
var $input = $(this);


$input.on('keyup change', function () {
touchButtons();
});
});


};

Now just loop thru the forms on the page and you should see submit buttons disabled by default and they will be activated ONLY if you indeed will change some input value on the form.

$('form').each(function () {
bindFormChange($(this));
});

Implementation as a jQuery plugin is here https://github.com/kulbida/jmodifiable

小开

$('form[name="your_form_name"] input, form[name="your_form_name"] select').click(function() {
$("#result").html($(this).val());
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<h2>Form "your_form_name"</h2>
<form name="your_form_name">
<input type="text" name="one_a" id="one_a" value="AAAAAAAA" />
<input type="text" name="one_b" id="one_b" value="BBBBBBBB" />
<input type="text" name="one_c" id="one_c" value="CCCCCCCC" />
<select name="one_d">
<option value="111111">111111</option>
<option value="222222">222222</option>
<option value="333333">333333</option>
</select>
</form>
<hr/>
<h2>Form "your_other_form_name"</h2>
<form name="your_other_form_name">
<input type="text" name="two_a" id="two_a" value="DDDDDDDD" />
<input type="text" name="two_b" id="two_b" value="EEEEEEEE" />
<input type="text" name="two_c" id="two_c" value="FFFFFFFF" />
<input type="text" name="two_d" id="two_d" value="GGGGGGGG" />
<input type="text" name="two_e" id="two_f" value="HHHHHHHH" />
<input type="text" name="two_f" id="two_e" value="IIIIIIII" />
<select name="two_g">
<option value="444444">444444</option>
<option value="555555">555555</option>
<option value="666666">666666</option>
</select>
</form>
<h2>Result</h2>
<div id="result">
<h2>Click on a field..</h2>
</div>

In addition to above @JoeD's answer.

If you want to target fields in a particular form (assuming there are more than one forms) than just fields, you can use the following code:

$('form[name="your_form_name"] input, form[name="your_form_name"] select').click(function() {
// A form element was clicked
});

小开

var formStr = JSON.stringify($("#form").serializeArray());
...
function Submit(){
var newformStr = JSON.stringify($("#form").serializeArray());
if (formStr != newformStr){
...
formChangedfunct();
...
}
else {
...
formUnchangedfunct();
...
}
}

小开

Try this:

<script>
var form_original_data = $("form").serialize();
var form_submit=false;
$('[type="submit"]').click(function() {
form_submit=true;
});
window.onbeforeunload = function() {
//console.log($("form").submit());
if ($("form").serialize() != form_original_data && form_submit==false) {
return "Do you really want to leave without saving?";
}
};
</script>