CODEWITHSUNDEEP
jquery
Computer User
Computer User

Reputation: 2879

Code to check if file exists in JQuery is not working

My JQuery code:

<script>

jQuery(document).ready(function() {

 var response = jQuery.ajax({

  url: 'filename.jpg',
  type: 'HEAD',
  async: true,

  error: function()
  {
   return "file does not exist";
  },
  success: function()
  {
   return "file exists";
  }

 });

 alert (response);

});

</script>

does not return anything. It should return either "file does not exist" or "file exists" and the message should be shown in an alert box. But the alert box has [object Object] value instead.

Upvotes: 0

Views: 516

Answers (1)

Lex
Lex

Reputation: 68

Ajax is asynchronous. When you call alert (response); response has not been resolved yet. I suggest something like this:

jQuery(document).ready(function() {
    jQuery.ajax({
         url: 'filename.jpg',
         type: 'HEAD',
         async: true,

         error: function()
         {
             handleResponse("file does not exist");
         },
         success: function()
         {
             handleResponse("file exists");
         }
     });

 });

 function handleResponse(response){
      alert(response);
 }

or just move the alert into the error/success functions.

Alternatively, you can do it like this:

loadAnImage = new Image();
loadAnImage.onload = function() {/*success*/}
loadAnImage.onerror = function() {/*error*/}
loadAnImage.src = "/*URL HERE*/";

Upvotes: 2

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