//only alpha numeric and underscore "_" will be allowed
function block_special_chars(){

    if ((event.keyCode > 31 && event.keyCode < 48) 
        || (event.keyCode > 57 && event.keyCode < 65) 
        || (event.keyCode > 90 && event.keyCode < 95)
        || event.keyCode==96 || event.keyCode > 122 ) 
    
        event.returnValue = false;
}


/* right trim a string */
 function rtrim(str)
{
	for (var i = str.length - 1; i >= 0; i--)
	{
		if (str.charAt(i) != ' ')
			break;
		str = str.substring(0, i);
	}
	return str;
}

/* left trim a string */
 function ltrim(str)
{
	for (var i =0; i<= str.length - 1; i++)
	{
		if (str.charAt(i) != ' ')
			break;
	}

	str = str.substring(i,str.length);
	return str;
}

/* combine right and left trim functions to a full trim function */
function trim(str)
{
	str=rtrim(str);
	str=ltrim(str)
	return str;
}

function isBlank(val)
{
	val=trim(val);
	if (val==""){
		return true;
	}
	    return false;
}

function validatePwd() {
  var invalid = " "; // Invalid character is a space
  var minLength = 4; // Minimum length
  var pw1 = document.myForm.password.value;
  var pw2 = document.myForm.password2.value;
  // check for a value in both fields.
  if (pw1 == '' || pw2 == '') {
    alert('Please enter your password twice.');
    return false;
 }
 // check for minimum length
  if (document.myForm.password.value.length < minLength) {
    alert('Your password must be at least ' + minLength + ' characters long. Try again.');
    return false;
  }
  // check for spaces
  if (document.myForm.password.value.indexOf(invalid) > -1) {
    alert("Sorry, spaces are not allowed.");
    return false;
  }
  else {
    if (pw1 != pw2) {
      alert ("You did not enter the same new password twice. Please re-enter your password.");
      return false;
    }
    else {
      return true;
    }
   }
}