Spaces in URLs are illegal. This is not a Netscape shortcoming. It is a matter of you not having written proper code.
See the documentation for rawurlencode() and urlencode(), and note that they are functions that return modified strings. They do not modify the original arguments. Thus, you might do something like this:
<a href="foo.php?bar=<? echo rawurlencode($bar) ?>">click here</a>
... and $bar itself would be unmolested.
