JAvascript does not validate for input box

programming web dev
1

Please help !

I have text input field that simple needs to validate if an amount is 250 or greater then it can process the form and redirect or else if
it lower it must show the error message. The code does not seem to get called


<script type="text/javascript">
function isNumber(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}
function validateForm(obj) {
   if (obj.amount.value == '') {
      document.getElementById("error").innerHTML = 'Please enter any amount!';
      return false;
   }

   if (!isNumber(obj.amount.value) && obj.amount.value < 250) {
      document.getElementById("error").innerHTML = 'Value must be equal or greater than 250';
      return false;
   }

   return true;
}
</script>

        <form method="post" action="https://www.moneybookers.com/app/payment.pl" onsubmit="return validateForm(this);">
        
            <p><span class="error">*required field.</span></p>
            Amount:<input type="text" name="amount"/>
            <span class="error" id="error"></span><bR>
            
             <input type="hidden" name="pay_to_email" value="someone.com"/>
             <input type="hidden" name="status_url" value="someone.com"/>
             <input type="hidden" name="return_url" value="http://wwww.somesite.com"/>
             <input type="hidden" name="language" value="EN"/>
             <input type="hidden" name="currency" value="USD"/>
             <input type="hidden" name="detail1_description" value="New Deposit"/>
             <input type="hidden" name="detail1_text" value="New Deposit"/><BR>
             <input type="submit" value="Deposit!"/>
             </form>