CODEWITHSUNDEEP
javascripthtml
Antman
Antman

Reputation: 493

Uncaught ReferenceError: onchange function is not defined

I am trying to upload an image and check whether this is a valid image with a Javascript function.

function validateImage() {
  var formData = new FormData();

  var file = document.getElementById("img").files[0];

  formData.append("Filedata", file);
  var t = file.type.split('/').pop().toLowerCase();
  if (t != "jpeg" && t != "jpg" && t != "png" && t != "bmp" && t != "gif") {
    alert('Please select a valid image file');
    document.getElementById("img").value = '';
    return false;
  }
  if (file.size > 1024000) {
    alert('Max Upload size is 1MB only');
    document.getElementById("img").value = '';
    return false;
  }
  return true;
}
<form action="/upload" method="post" enctype="multipart/form-data">
  Image<input type="file" name="upl" accept="image/*" onchange="validateImage()"><br>
  <input type="submit" value="Submit">
</form>

The function validateImage() is not called and the next message is displayed:

Uncaught ReferenceError: validateImage is not defined at HTMLInputElement.onchange

Any idea?

Upvotes: 3

Views: 11412

Answers (1)

connexo
connexo

Reputation: 56773

You have no element with id="img". Add the id or choose a different method to select the file input in your JS code.

function validateImage() {
  console.log("validateImage called");
  var formData = new FormData();

  var file = document.getElementById("img").files[0];

  formData.append("Filedata", file);
  var t = file.type.split('/').pop().toLowerCase();
  if (t != "jpeg" && t != "jpg" && t != "png" && t != "bmp" && t != "gif") {
    alert('Please select a valid image file');
    document.getElementById("img").value = '';
    return false;
  }
  if (file.size > 1024000) {
    alert('Max Upload size is 1MB only');
    document.getElementById("img").value = '';
    return false;
  }
  return true;
}
<form action="/upload" method="post" enctype="multipart/form-data">
  Image<input id="img" type="file" name="upl" accept="image/*" onchange="validateImage()"><br>
  <input type="submit" value="Submit">
</form>

Upvotes: 2

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