I needed a function in PHP to do the same job as the complete escape function in Javascript. It took me some time not to find it. But findaly I decided to write my own code. So just to save time:
<?php
function fullescape($in)
{
 $out = '';
 for ($i=0;$i<strlen($in);$i++)
 {
 $hex = dechex(ord($in[$i]));
 if ($hex=='') 
 $out = $out.urlencode($in[$i]);
 else 
 $out = $out .'%'.((strlen($hex)==1) ? ('0'.strtoupper($hex)):(strtoupper($hex)));
 }
 $out = str_replace('+','%20',$out);
 $out = str_replace('_','%5F',$out);
 $out = str_replace('.','%2E',$out);
 $out = str_replace('-','%2D',$out);
 return $out;
 }
?>

It can be fully decoded using the unscape function in Javascript.