Regular expression to extract the value of hidden element

I have html pages with hidden element as below:

< input type=hidden id="xl_aux2" name="xl_aux2" value="???" >

Value contains base64 string. So what will be the regular expression that I can use to extract the value开发者_JS百科 from above hidden element?

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One possibility:

value="([^"]*)"

The data you want is in the first group.

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There is an answer with regular expression for Base64 encoded string :

RegEx to parse or validate Base64 data

So the result expression will be like this :

/.*value=\"(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?\".*/