getElementById问题

Question

I have got this button:

<input type="button" value="Rep" 
    id="rep" name="rep" class="rep" style="width:50px" 
    onclick="triggerLabel(1);this.disabled=true;addRep(<?php echo  $comment_id; ?>);"/>

<script type="text/javascript">

     function triggerLabel($commentID)
     {
        var $theID="#"+$commentID;
        var $label=document.getElementById($theID).value;
        alert($label);
     }

</script>

The alert isn't triggered. I want to obtain the commentID and convert it to a string.. And I want that string to represent my element ID. The alert works, it retrieves #25. That's the id that I gave one of my labels..

echo '<label id="'.$comment_id.'">'.$avatarRep.'</label>';

It should retrieve that label, but unfortunately it fails..I get this:

Error: document.getElementById($theID) is null Source File: http://localhost/PoliticalForum/Thread/thread.php?threadID=15&page=1 Line: 246

What do I do?

That's how the label html control looks like when I view the source page:

<label id="25">6</label>

UPDATE: I updated my answer. Take a look:

var $label=document.getElementById($commentID);
$label.value=9999;

The 9999 isnt inserted into the table..why?!?

UPDATE 2: This doesnt work:

document.getElementById($commentID).value="88888";

The label isnt changed.

Answer 1

You do not have to supply the # for getElementById . Just the ID. So write:

var $label=document.getElementById($commentID).value;

Another option is to get the element via the JQuery $ function. Then you have to supply the # :

var $label=$($theID).val()

Answer 2

document.getElementById("your_id_without_#_char") will return you HTML element.

$("#your_id_with_#_char") will return you jQuery object.

You shouldn't use # for document.getElementById() function - just elem ID.

Answer 3

Not add the "#" to your CommentID. write:

 function triggerLabel($commentID)
 {
    var $theID=$commentID;
    var $label=document.getElementById($theID).value;
    alert($label);
 }

Answer 4

document.getElementById()不是jQuery，它是DOM函数，因此您无需在id的前面放置#

Answer 5

Either use getElementById properly, ie remove the # :

var $label = document.getElementById($commentID);

or use jQuery:

var $label = $($theID);

Note that label s don't have a value property. If you want to get the inner text, use innerHTML or .text() with jQuery.

Also, before HTML5, IDs where not allowed to start with digits.

Answer 6

If you want to use the # in front of your id, you can use the querySelector method, but is not compatible with older browsers.

Incompatible with: IE < 8, FFox < 3.5, Opera < 10, Safari < 3.2

https://developer.mozilla.org/En/DOM/Document.querySelector

document.querySelector('#id');

You should not use the hash in your case

document.getElementById('#id');

in jquery you can use the hash

$('#id');