Can't set hidden input field's value using jQuery

问题

I have a simple input field inside a form tag:

<body>
  <form action="#">
      <label>Input</label>
      <input type="hidden" id="foo" name="foo" />

  </form>
</body>

I tried to set this value from a js file:

$(document).ready(function(){
    $('#foo').val('foo')
})

but in the html source the attribute isn't set at all. If I try to set the input type to "button" or anything else, it works. I just can't do it with a hidden input field. What am I doing wrong?

回答1:

Can you retrieve the value from the hidden field if you set the val tag?

e.g.

<input type="hidden" id="foo" name="foo" value="bar" />

$(document).ready(function(){
  alert($('#foo').val());
})

回答2:

I figured it out. The value was set by jQuery but when I viewed the source the new value wasn't shown. I tried this (thanks to Fermin):

$('#foo').val('poo')
alert($('#foo').val())

and it displayed the modified value.

回答3:

The best answer I found was in the form http://forum.jquery.com/topic/passing-value-to-hidden-form-field.

Instead of $('#Data').val(data); Where the hidden field ID is 'Data'

Use $('input[name=Data]').val(data);

Works perfectly for me

回答4:

I have also been struggling with this. If you set an initial value say '0', and then watch the DOM using something like Firebug you will notice that the DOM then updates. For some reason if the initial value is set to null or an empty string, the DOM does not update, but the value is actually still stored.

You can test this by alerting the val after you have set it (as suggested in earlier posts)

回答5:

I've had this problem when POST-ing my form and my PHP script couldn't get POST-ed value. I used this:

$('#elemId').attr("name", theValue);

Hope it helps.

回答6:

I'd need to see the whole file but my guess is either you aren't including the jQuery.js source file or you have multiple elements with an ID of foo

回答7:

I had the same problem with a hidden input field. Id i set the initial value on 0, it works fine, but sometimes i didn't want to have an initial value of 0. So i tested with value=" ", a whitespace, and it works for me too. If you fill the value dynamic from PHP you could do value="<?= $val+0; ?>" if 0 is fine for you, or value="<?= $val; ?> " if a whitespace is fine.

回答8:

I know that it's to late but still this might help someone.... If none of the above solutions work, just do this...

$(document).ready(function() {
$('#foo').attr("value","foo") });

回答9:

None of the above solutions worked for me.

I had to do the following to make it work:

$('#foo').val(data).blur();

回答10:

Rather then initialising your value attribute with an string initialise your input like this.

<input type="hidden" name="foo" id="foo" value="${foo}">

"foo" will contain the new value you set it too.

回答11:

I've confirmed that setting the value of a hidden field does not work with a jQuery selector like this...

$('[name="my_field"]').val('Something');

Will not update a hidden field... kinda shocking.

<input type="hidden" name="my_field" id="my_field">

Was forced to use a CSS hidden field instead.

<input type="text" name="my_field" id="my_field" style="display:none">

Apparently there are other issues with using the id of a hidden field as well... Set value of hidden field in a form using jQuery's ".val()" doesn't work

Note: be sure to obtain the value in the console and not by inspecting.

$('[name="my_field"]').val();

来源：https://stackoverflow.com/questions/2109322/cant-set-hidden-input-fields-value-using-jquery

标签

jquery

hidden-field