JQuery: Change value of hidden input field

hidden-fieldjquery

I'm having a hella time setting the value of a hidden input.

I want to pass the HTML from between the option tags to the hidden field- end run it will the page title from wordpress' wp_list_dropdowns(). I've got it returning the text just fine, and on my change event it correctly adds some css (obviously unneeded on a hidden field, but I was trying to determine where things are breaking down). Works if I change the hidden input to a text input. I've seen in several places on SO that this is possible, (changing the value of a hidden input that is), but something is holding me up now and I can't see the answer.

Here's the JSFiddle:

JavaScript:

$(".selector").change(function() {
    var $value = $(this).val();
    var $title = $(this).children('option[value='+$value+']').html();
    alert($title); 
    $('input#bacon').val($title).css('border','3px solid blue');
});

HTML:

<select class="selector" name="testselect">
    <option value="1">One</option>
    <option value="2">Two</option>
    <option value="3">Three</option>
</select>
</h3>

<input id="bacon" type="hidden" class="bacon" value="" name="testinput">

Best Answer

It's simple as:

$('#action').val("1");

#action is hidden input field id.

Related Solutions

Javascript – n “exists” function for jQuery

In JavaScript, everything is 'truthy' or 'falsy', and for numbers 0 means false, everything else true. So you could write:

if ($(selector).length)

You don't need that >0 part.

Javascript – How to upload files asynchronously with jQuery

With HTML5 you can make file uploads with Ajax and jQuery. Not only that, you can do file validations (name, size, and MIME type) or handle the progress event with the HTML5 progress tag (or a div). Recently I had to make a file uploader, but I didn't want to use Flash nor Iframes or plugins and after some research I came up with the solution.

The HTML:

<form enctype="multipart/form-data">
    <input name="file" type="file" />
    <input type="button" value="Upload" />
</form>
<progress></progress>

First, you can do some validation if you want. For example, in the .on('change') event of the file:

$(':file').on('change', function () {
  var file = this.files[0];

  if (file.size > 1024) {
    alert('max upload size is 1k');
  }

  // Also see .name, .type
});

Now the $.ajax() submit with the button's click:

$(':button').on('click', function () {
  $.ajax({
    // Your server script to process the upload
    url: 'upload.php',
    type: 'POST',

    // Form data
    data: new FormData($('form')[0]),

    // Tell jQuery not to process data or worry about content-type
    // You *must* include these options!
    cache: false,
    contentType: false,
    processData: false,

    // Custom XMLHttpRequest
    xhr: function () {
      var myXhr = $.ajaxSettings.xhr();
      if (myXhr.upload) {
        // For handling the progress of the upload
        myXhr.upload.addEventListener('progress', function (e) {
          if (e.lengthComputable) {
            $('progress').attr({
              value: e.loaded,
              max: e.total,
            });
          }
        }, false);
      }
      return myXhr;
    }
  });
});

As you can see, with HTML5 (and some research) file uploading not only becomes possible but super easy. Try it with Google Chrome as some of the HTML5 components of the examples aren't available in every browser.

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