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

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