The problem is that there are a fair number of people who are people who
are still using older browsers, especially outside of the US. I use
IE5.5 because I never bothered to upgrade from Win95. I have clients
who still use Netscape 4.7. One of my Mac based clients has IE5 on all
of their machines. I couldn't use my ISP's webmail client, because the
MAC IE5 _javascript_ was braindead. Also, some people turn off
_javascript_.
Netscape start to support _javascript_ since 2.0. _javascript_ itself is never the reason cause those problem (beside people turn it off). The problem is on Netscape 4.7, IE5 or Mac IE is the level of DOM support. You are completed confused between _javascript_ language itself and the API hook into the browser - DOM- DOM level 0, DOM level 2 or DOM level 3.
All of the browser you mention do have _javascript_ support, they may have different version of the support for _javascript_ and DOM but they all have _javascript_ support unless user turn the _javascript_ off.
I also do not agree with your argument against PHP. PHP is totally
server side. I have has my PHP applicaions work with browsers from
Netscape 4.7 to IE6, Opera, and Netscape 7. I have also had my hosting
provider change PHP version on my, and my code hasn't broken.
