Preserving case / capitalization with JavaScript replace method

I'm continuing work on a search term suggestion tool using Jquery UI. I am now working on displaying the results with the search term pattern in bold. I have implemented this functionality through patching the Autocomplete's _renderItem method. The problem I have now is that the replaced characters have the same case as those typed by the user in the input (e.g. if the user typed an "A" and t开发者_JAVA百科he returned result was "America", the replaced text would be AmericA. Here's the code:

    var exp = new RegExp(this.term, "gi") ;
    var rep = item.label.replace( exp, "<span style='font-weight:bold;color:Black;'>"
    + this.term + "</span>");

As always, thanks in advance for any help.

You can use:

var rep = item.label.replace(exp,
                             "<span style='font-weight:bold;color:Black;'>$&</span>");

When replacing a string, $& means "the whole match", so you don't have to repeat the search term (in some cases you don't know it). In other flavors, you may use $0 or \0.
Also, remember to escape special characters in this.term.

You can add your expression in a group by encapsulating them in parentheses

var exp = new RegExp("(" + this.term + ")", "gi") ;
var rep = item.label.replace( exp, "<span style='font-weight:bold'>$1</span>");

You can the refere to that group using $1.

See here for more details about backreferences.