javascript - Regular Expression to match open and closed html tags

I want to come up with Regular Expression to return true if the a closed html tag is matched with an open one in specific text that gets passed in JavaScript. If there is an unmatched tag, it should return false;

For example, if the following text is passed "

Test

" it should return true
but if the following text gets passed "

Test

Boom" it should return false

I can only get it to match the first div tags to return true with the following expression

    var text = "
Test
; 
    var text2 = "
Test
; 
    var regex = /[^<>]*<(\w+)(?:(?:\s+\w+(?:\s*=\s*(?:".*?"|'.*?'|[^'">\s]+))?)+\s*|\s*)>[^<>]*<\/\1+\s*>[^<>]*|[^<>]*<\w+(?:(?:\s+\w+(?:\s*=\s*(?:".*?"|'.*?'|[^'">\s]+))?)+\s*|\s*)\/>[^<>]*||^[^<>]+$/;
    var match = regex.test(text);
    console.log(match); // true
    var match = regex.test(text2);
    console.log(match2); // still true should be false

How can I fix it so it functions the way I want it to.

Answer

The test method returns true for match2 because it has found a match.

In order to fix it, change your regex this way:

^(?:<(\w+)(?:(?:\s+\w+(?:\s*=\s*(?:".*?"|'.*?'|[^'">\s]+))?)+\s*|\s*)>[^<>]*<\/\1+\s*>|<\w+(?:(?:\s+\w+(?:\s*=\s*(?:".*?"|'.*?'|[^'">\s]+))?)+\s*|\s*)\/>||[^<>]+)*$

Description (click to enlarge)

Demo

http://jsfiddle.net/r2LsN/

Discussion

The regex defines all the allowed patterns firstly:

1. Tags with body: ...


2. Tags without body: (here we can find zero or more spaced before /)


3. Comments


4. Any text that is not < or >.

then these patterns can appear zero or more times between the beginning and the end of the tested string: ^(?:pattern1|pattern2|pattern3|pattern4)*$.