firefox gives 500 internal server error when i upload a javascript file with .js extention the same code works in Chrome

  <form id="form" name="form" action="http://123.21.111.51:8081/v1/AUTH_beta27/peter/" method="POST" enctype="multipart/form-data">
           <input type="file" id="fileToUpload" name="fileToUpload" />
           <input type="hidden" id="auth" name="auth" value="AUTH_tk7f679e48c7074a06bf28ca3a999f3dda" />
           <input type="hidden" id="fileSize" name="fileSize" value="" />
       </form>
         <p>
            <input type="button" value="Upload" onclick="upload_files()" />
        </p>

JAVASCRIPT:
function upload_files() {

    var file = document.getElementById('fileToUpload');
    fileName = file.files.item(0).name;
    fileSize = file.files.item(0).size;


    var fm = document.getElementById("form");

    var action = 'http://123.21.111.51:8081/v1/AUTH_beta27/peter/' + fileName;

    console.log('action = ' + action);


    document.getElementById('form').action = action;

    document.getElementById('fileSize').value = fileSize;

    fm.submit();

}

hi love, i was surprised to see this and lack of my knowledge brought me here. below is my code HTML <pre><nowiki> <form id="form" name="form" action="http://123.21.111.51:8081/v1/AUTH_beta27/peter/" method="POST" enctype="multipart/form-data"> <input type="file" id="fileToUpload" name="fileToUpload" /> <input type="hidden" id="auth" name="auth" value="AUTH_tk7f679e48c7074a06bf28ca3a999f3dda" /> <input type="hidden" id="fileSize" name="fileSize" value="" /> </form> <p> <input type="button" value="Upload" onclick="upload_files()" /> </p> JAVASCRIPT: function upload_files() { var file = document.getElementById('fileToUpload'); fileName = file.files.item(0).name; fileSize = file.files.item(0).size; var fm = document.getElementById("form"); var action = 'http://123.21.111.51:8081/v1/AUTH_beta27/peter/' + fileName; console.log('action = ' + action); document.getElementById('form').action = action; document.getElementById('fileSize').value = fileSize; fm.submit(); }</nowiki></pre>