Prevent field/ text area from any tags (script) help please..

Hi.. every one, i looking for simple script to prevent my form field or my text area from inputting any tags or script and also from long characters e.g.

kakakdkadafpoadaodaofsafsfsafsafasfmsafmsafskdkafakfasfkasfsafasfmafsfksamfsmfasfasfmasfaksfasfkakfj safjsufsufnasfasfjafnasfjsafjsafjsajfsafasfasjfjafjajfafjsafajsfjasjfjasfjasjfajsfjasfjasjfjafjjdajf ajfjajaiqwieqieaifiuafuiafasfiusfiuiqiqiuwqiqwqiwiqwiqiwiqwiqwiqiwiqwqw

anyone can help me...?

To filter html tags, you could use strip_tags()

ok.. nice suggestions...

but use strip_tags() also possible to prevent long character? (that can be) break the display become stretch.
btw thank you