CODEWITHSUNDEEP
jquery
Afzaal Ahmad Zeeshan
Afzaal Ahmad Zeeshan

Reputation: 15860

Why does this provide me with undefined; jQuery

I am using parent() and find() method to access the textarea of the correspoding button.

But I get undefined each time. I have tried it in a jsfiddle, but that fiddle works. Here is the code

<div>
  <textarea id="textarea"></textarea>
  <button onclick="commentThis('10')">Post Comment</button>
  <button onclick="neverMind('10')">Never Mind</button>
</div>

jQuery code is as 

function commentThis(postId) {
   var comment = $(this).parent().find("#textarea").val();
   if (comment != "" || comment != null) {
     $.ajax({
       url: "/ajax_requests/post_comment",
       data: "postId=" + postId + "&type=comment&comment=" + 
       comment + "&page=default",
       success: function (result) {
          $(".comments").append(result);
          $("#textarea").val("");
          $("#textarea").css("height", "20px");
       }
     })
   }
}

But it always give me a console error of undefined, saying value cannot be taken from undefine attribute.

You can see the error message here:

enter image description here

here is the fiddle that I created and which works. http://jsfiddle.net/afzaal_ahmad_zeeshan/ZBcby/

Upvotes: 0

Views: 39

Answers (2)

nnnnnn
nnnnnn

Reputation: 150030

When you call your function like this:

onclick="commentThis(@row.PostId)"

...it doesn't set the value of this to the element that was clicked. this will be window. You could change it to explicitly set the value of this:

onclick="commentThis.call(this,@row.PostId)"

You will also need to change the following line of your function:

if (comment != "" || comment != null) {

because that if condition will always be true because either comment != "" will be true or comment != null will be true. You probably meant to use && instead of ||:

if (comment != "" && comment != null) {

...but you can simplify that to this:

if (comment) {

(And in practice given that comment is the result of calling .val() it won't ever be null anyway, it will either be a string or undefined - and if you get the selector right it won't be undefined.)

Upvotes: 1

lonesomeday
lonesomeday

Reputation: 237865

if (comment.value != "" || comment.value != null) {

You got the value with val(). You therefore have a string. You are attempting to get the value property of a string. This won't work.

This will:

if (comment != "" || comment != null) {

Or, in fact, even simpler:

if (comment) {

Upvotes: 2

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