It is better to use some ready-to-eat kind of CPAN module. However if you want a simple soltion then here it is.
It will work for following kinds of tags
1) <script> ( should be deleted )
2) <script a="aaa"> (should be deleted )
3) <script1> (This should be retained by regex)
4) ANY OTHER TAG other than mentioned above (This should be retained by regex)
## This is required so that we can escape processing of tags like <scr
+ipt1>, <scriptabc>,<scriptxyz>....etc from deletion
s/<script>/<script >/igs;
s/<script\ .*?>.*?<\/script>//igs;