Javascript replace() with case-change

Question

Is there an easy way to change the case of a matched string with javascript?

Example

String :

something

<

Answer 1

You can pass the replace method a replacer function. The first argument for which is the whole match, the second will be $1. Thus:

mystring.replace(/<([\w]+)[^>]*>.*?<\/\1>/, function(a,x){ 
   return a.replace(x,x.toUpperCase()); 
})

although this form saves the extra operation by making an additional capture (should be faster but haven't checked):

mystring.replace(/<([\w]+)([^>]*>.*?<\/\1>)/, function(a,x,y){ 
   return ('<'+x.toUpperCase()+y); 
})