function isValidEmail(str) {
   return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
 
}

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

function ValidateForm(form)
{
   if(IsEmpty(form.gname)) 
   { 
      alert('please enter your name') 
      form.gname.focus(); 
      return false; 
   } 
   if(IsEmpty(form.gtext)) 
   { 
      alert('please enter your text') 
      form.gtext.focus(); 
      return false; 
   } 
 
 
   if (form.gemail.value!="" && !isValidEmail(form.gemail.value)) 
   { 
      alert('please enter a valid email address') 
      form.gemail.focus(); 
      return false; 
      } 
 
return true;
 
} 

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;
   
   }