function validateFields(){
	var uploadform=document.forms['upload'];
	var filename=uploadform.file.value;
	var username=uploadform.username.value;
	var email=uploadform.email.value;
	var isValid=validateUserName(username) & validateEmail(email) & validateFileName(filename);
	if (isValid) {
		uploadform.submit();
	}
}

function validateFileName(filename){
	if (filename==null || filename.length<1){
		var element=document.getElementById('filename_error');
		element.style.display='block'
		element.innerHTML="Select a file";
		return false;
	}else {
		var element=document.getElementById('filename_error');
		element.style.display='none'
		return true;
	}

}

function validateUserName(username){
	if (username==null || username.length<1){
		var element=document.getElementById('username_error');
		element.style.display='block'
		element.innerHTML="Enter a name";
		return false;
	}else {
		var element=document.getElementById('username_error');
		element.style.display='none'
		return true;
	}

}

function validateEmail(email) {
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   var address = email
   if(reg.test(address) == false) {
      	var element=document.getElementById('email_error');
		element.style.display='block'
		element.innerHTML="Enter valid email address";
		return false;
   	}else {
		var element=document.getElementById('email_error');
		element.style.display='none'
		return true;
	}
}