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>

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>

• javascript
• html

• <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 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 Commented Nov 8, 2015 at 19:46
• This code i use how i done javascript maximum size validation in this code. – Arslan Khalil Commented Nov 8, 2015 at 19:46

1 Answer 1

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>