// JavaScript Document

function IsEmpty(aTextField) {
   if ((aTextField.value.length==0) ||
   (aTextField.value==null)) {
      return true;
   }
   else { return false; }
}

function IsNumeric(sText)

{
   var ValidChars = "0123456789() ";
   var IsNumber=true;
   var Char;

 
   for (i = 0; i < sText.length && IsNumber == true; i++) 
      { 
      Char = sText.charAt(i); 
      if (ValidChars.indexOf(Char) == -1) 
         {
         IsNumber = false;
         }
      }
   return IsNumber;
   
   }


function check(form)
{

   if(IsEmpty(form.Name)) 
   { 
      alert('Please enter your name') 
      return false; 
   } 
 
 if(IsEmpty(form.Phone)) 
   { 
      alert('Please enter your telephone number') 
      return false; 
   } 
 
   if (!IsNumeric(document.forms[0].Phone.value)) 
   { 
      alert('Please enter only numbers in the telephone number field') 
      return false; 
      } 
 
return true;
 
}