Detect when an image fails to load in Javascript

Question

Is there a way to determine if a image path leads to an actual image  Ie  detect when an image fails to load in Javascript   For a web app  I am parsing a xml file and dynamically creating HTML images from a list of image paths  Some image paths may no longer exist on the server so I want to fail gracefully by detecting which images fail to load and deleting that HTML img element   Note JQuery solutions wont be able to be used the boss doesn t want to use JQuery  yes I know dont get me started   I know of a way in JQuery to detect when an image is loaded  but not whether it failed   My code to create img elements but how can I detect if the img path leads to a failed to load image   var imgObj   new Image        document createElement  img    imgObj src   src

User · Answer

Here s a function I wrote for another answer  Javascript Image Url Verify   I don t know if it s exactly what you need  but it uses the various techniques that you would use which include handlers for onload  onerror  onabort and a general timeout   Because image loading is asynchronous  you call this function with your image and then it calls your callback sometime later with the result

User · Answer

jQuery   CSS for img  With jQuery this is working for me       img   error function           this  attr  src     no-img png   addClass  no-img          And I can use this picture everywhere on my website regardless of the size of it with the following CSS3 property    img no-img       object-fit  cover      object-position  50  50          TIP 1   use a square image of at least 800 x 800 pixels       TIP 2   for use with portrait of people  use object-position  20  50     CSS only for background-img  For missing background images  I also added the following on each background-image declaration    background-image  url  path-to-image png    url  no-img png         NOTE   not working for transparent images    Apache server side  Another solution is to detect missing image with Apache before to send to browser and remplace it by the default no-img png content   RewriteCond   REQUEST FILENAME   -f RewriteCond   REQUEST URI   images      gif jpg jpeg png   RewriteRule     images no-img png  L R 307

User · Answer

Tests image load      param  String  url     returns  Promise      function testImageUrl url      return new Promise function resolve  reject        var image   new Image        image addEventListener  load   resolve       image addEventListener  error   reject       image src   url           return testImageUrl imageUrl  then function imageLoaded e      return imageUrl      catch function imageFailed e      return defaultImageUrl

User · Answer

You could try the following code  I can t vouch for browser compatibility though  so you ll have to test that   function testImage URL        var tester new Image        tester onload imageFound      tester onerror imageNotFound      tester src URL     function imageFound         alert  That image is found and loaded       function imageNotFound         alert  That image was not found        testImage  http   foo com bar jpg      And my sympathies for the jQuery-resistant boss

User · Answer

The answer is nice  but it introduces one problem  Whenever you assign onload or onerror directly  it may replace the callback that was assigned earlier  That is why there s a nice method that  registers the specified listener on the EventTarget it s called on  as they say on MDN  You can register as many listeners as you want on the same event   Let me rewrite the answer a little bit   function testImage url        var tester   new Image        tester addEventListener  load   imageFound       tester addEventListener  error   imageNotFound       tester src   url     function imageFound         alert  That image is found and loaded       function imageNotFound         alert  That image was not found        testImage  http   foo com bar jpg      Because the external resource loading process is asynchronous  it would be even nicer to use modern JavaScript with promises  such as the following   function testImage url            Define the promise     const imgPromise   new Promise function imgPromise resolve  reject                Create the image         const imgElement   new Image                When image is loaded  resolve the promise         imgElement addEventListener  load   function imgOnLoad                 resolve this                           When there s an error during load  reject the promise         imgElement addEventListener  error   function imgOnError                 reject                           Assign URL         imgElement src   url                return imgPromise     testImage  http   foo com bar jpg   then       function fulfilled img            console log  That image is found and loaded   img               function rejected             console log  That image was not found

User · Answer

just like below   var img   new Image     img src   imgUrl    if   img complete       has picture   else   not

User · Answer

This    lt img onerror  this src   images image png   src       gt

[javascript] Detect when an image fails to load in Javascript

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