php - PHPコードでJavaScriptブール出力を使用するには?

Question

registerUser()関数を呼び出すにはどうすればよいですか

if (formvalidate()==true); // i am trying here
registerUser(); // shall be called if formvalidate() is true

私が使用しているコードは次のとおりです。

<?PHP
 include("functions.php"); 
 if(isset($_POST['Submit1']))
{
 ?>
<script type="text/javascript">
if(formvalidate()==true);//i am trying here
registerUser();this will do if formvalidat return true
helloworld();

<?php }; ?>
  <script type="text/javascript">
function formvalidate()
{
if( document.Form.first_name.value == "" )
   {
     alert( "Please insert your name." );
     document.Form.first_name.focus() ;
     return false;
   }
   if( document.Form.last_name.value == "" )
   {
     alert( "Please insert your last name." );
     document.Form.last_name.focus() ;
     return false;
   }
   if( document.Form.password.value == "" )
   {
     alert( "Please insert your password." );
     document.Form.password.focus() ;
     return false;
   }
   if( document.Form.username.value == "" )
   {
     alert( "Please insert your user name(display name) ." );
     document.Form.username.focus() ;
     return false;
   }
   if ( ( Form.gender[0].checked == false ) && ( Form.gender[1].checked == false ) ) 

   { 
    alert( "Please select your gender." );  
     document.Form.gender.focus() ;
     return false;
   }
         if( document.Form.birthdate_year.value == "" )
   {
     alert( "Please insert your birthyear." );
     document.Form.birthdate_year.focus() ;
     return false;
   }
         if( document.Form.birthdate_day.value == "" )
   {
     alert( "Please insert your birthDAY." );
     document.Form.birthdate_day.focus() ;
     return false;
   }
         if( document.Form.birthdate_month.value == "" )
   {
     alert( "Please insert your birthmonth." );
     document.Form.birthdate_month.focus() ;
     return false;
   }

   //gender $_POST['birthdate_year']."-".$_POST['birthdate_month']."-".$_POST['birthdate_day']
   if( !validateEmail())
   {
     alert( "Please insert your Email address." );
     document.Form.email.focus() ;
     return false;
   }
   if( document.Form.zip.value == "" ||isNaN( document.Form.Pin.value ) )
   {
     alert( "Please insert the pin code." );
     document.Form.zip.focus() ;
     return false;
   }
   if( document.Form.countries.value == "" )
   {
     alert( "Please select your country!" );
     return false;
   }
   return( true );
}

function validateEmail()
{

   var emailID = document.Form.email.value;
   atpos = emailID.indexOf("@");
   dotpos = emailID.lastIndexOf(".");
   if (atpos < 1 || ( dotpos - atpos < 2 )) 
   {

              return false;
   }
   return( true );
}
</script>