Replacing multiple patterns in a block of data

Question

I need to find the most efficient way of matching multiple regular expressions on a single block of text. To give an example of what I need, consider a block of text:

<

Answer 1

You can pass a function to replace:

var hello = "Hello World what a beautiful day";
hello.replace(/Hello|World/g, function ($0, $1, $2) // $3, $4... $n for captures
{
    if ($0 == "Hello")
        return "Bye";
    else if ($0 == "World")
        return "Universe";
});

// Output: "Bye Universe what a beautiful day";