Returns a string in which all non-alphanumeric characters except -_.~
have been replaced with a % followed by two hex digits
Spaces are encoded as %20
For spaces encoded as + signs use urlencode

<!--parser:xtscript-->
var $input =! "£ $%^&*+
var $output = call rawurlencode $val=$input
print input = $input<br />
print output = $output
<!--/parser:xtscript-->