Regular Expression for nested html tags

[mohanrajit.88]

Hi Guys,
I'm in need of regular expression for validating the html tags
that are closed properly,

say for example
<i>test content <b>see this </i> ..
it should show an alert "tag is incorrect".
Plz help me....Guys-:)-:)

Thanks in advance

[pritaeas]

I doubt this is possible by only using a regular expression. There are so many levels of nesting possible, I think you would need a parser instead.

[fxm]

It is relatively easy to detect a <tagx> which is followed by <tagy> before </tagx> is encountered, but that may not be an error.

Trivial counter-examples include <b>xxx<br></b> and <b>xxx<br /></b> and there is an endless supply of not so trivial cases.

It would be possible to test certain tags; beyond that the reply about needing a parser is on point.

[mohanrajit.88]

I doubt this is possible by only using a regular expression. There are so many levels of nesting possible, I think you would need a parser instead.

Pritaeas, you are right,it is possible by regular expression,I found the solution in php way it uses preg_match_all but i'm in need of alternative for it in java script.which should validate <b>,<i>,<u> tags that are closed properly or not.
Thanks:-/

[fxm]

Javescript RegExp will do _precisely_ what preg_match does.
Neither will solve the general problem, and even the three cases you have now given will not be easy.
Part of the difficulty is that "closed properly" != "closed".