jQuery: create regex pattern from variable

I'm trying to create a regex pattern out of a variable like:

var tag = "style";
var pattern = "/<"+tag+"[^>]*>((\\n|.)*)<\\/"+tag+">/开发者_StackOverflow社区gi";

but it won't work - anyone can tell me what's wrong?

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Use the RegExp object

var tag = "style";
var pattern = new RegExp("<"+tag+"[^>]*>((\\n|.)*)<\\/"+tag+">","gi");

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In general, matching html tags with regex isn't a good idea. See explanation here.

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var re = new RegExp(string) ..

see here