How to check maximum upload file size in javascript validation?

Question

I have a code but I need a javascript validation that checks maximum upload file size like check if the uploaded file is increased 1-MB he show error file is increased chosse less then 1MB file ...

I have this code how use maximum file size regular expression and whar code I use in this code that check maximum size validation.

<form action="" method="post">
 <script type="text/javascript">
   function ValidateExtension() {
     var allowedFiles = [".doc", ".docx", ".pdf"];
     var fileUpload = document.getElementById("fileUpload");
     var lblError = document.getElementById("lblError");
     var regex = new RegExp("([a-zA-Z0-9\s_\\.\-:])+(" + allowedFiles.join('|') + ")$");
     if (!regex.test(fileUpload.value.toLowerCase())) {
       lblError.innerHTML = "Please upload files having extensions: <b>" + allowedFiles.join(', ') + "</b> only.";
       return false;
     }
     lblError.innerHTML = "";
     return true;
   }
 </script>
<input id="fileUpload" type="file" /> 
<br /> 
<span id="lblError" style="color: red;"></span> 
<br /> 
<input type="submit" id="btnUpload" value="Upload" onclick="return ValidateExtension()" /> 
</form>

<form action="" method="post"> <script type="text/javascript"> function ValidateExtension() { var allowedFiles = [".doc", ".docx", ".pdf"]; var fileUpload = document.getElementById("fileUpload"); var lblError = document.getElementById("lblError"); var regex = new RegExp("([a-zA-Z0-9\s_\\.\-:])+(" + allowedFiles.join('|') + ")$"); if (!regex.test(fileUpload.value.toLowerCase())) { lblError.innerHTML = "Please upload files having extensions: <b>" + allowedFiles.join(', ') + "</b> only."; return false;} lblError.innerHTML = ""; return true;} </script> — Arslan Khalil
– Arslan Khalil, Commented Nov 8, 2015 at 19:45
<input id="fileUpload" type="file" /> <br /> <span id="lblError" style="color: red;"></span> <br /> <input type="submit" id="btnUpload" value="Upload" onclick="return ValidateExtension()" /> </form> — Arslan Khalil
– Arslan Khalil, Commented Nov 8, 2015 at 19:46
This code i use how i done javascript maximum size validation in this code. — Arslan Khalil
– Arslan Khalil, Commented Nov 8, 2015 at 19:46

Kenney · Accepted Answer · 2015-11-09 14:25:31Z

8

This should get you started.

function validate(el) {
  var maxfilesize = 1024 * 1024,  // 1 Mb
      filesize    = el.files[0].size,
      warningel   = document.getElementById( 'lbError' );

  if ( filesize > maxfilesize )
  {
    warningel.innerHTML = "File too large: " + filesize + ". Maximum size: " + maxfilesize;
    return false;
  }
  else
  {
    warningel.innerHTML = '';
    return true;
  }   
}

.warning { font-style: italic; }

<form enctype="multipart/form-data" method="POST">
  <input type='file' name='f' onchange='validate(this)'>
  <div id='lbError' class='warning'></div>
  <input type='submit' onsubmit='return validate()'/>
</form>

edited Nov 9, 2015 at 14:25

answered Nov 8, 2015 at 19:44

Kenney

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3 Comments

Arslan Khalil Over a year ago

Thnx but me not need this code i write code above in commeent how i check javascript validation that chaeck file size if file size is greater file is not uploaded

Kenney Over a year ago

There was, and is, code in there that you need: the expression to access the file size. I've updated the answer to be more inline with your code; all that's left for you to do is to merge that with your code.

Arslan Khalil Over a year ago

OK Thank u bro so much

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