(str)tr for JavaScript

I couldn't find a function resembling Ruby's tr or PHP's strtr in JavaScript, so I created one. Here's the code:

function tr(str, from, to) {
    var subst;
    for (i = 0; i < from.length; i++) {
        subst = (to[i]) ? to[i] : to[to.length-1];
        str = str.replace(new RegExp(str[str.indexOf(from[i])], 'g'), subst);
    }
    return str;
}

Java oddity

I really don't like the fact that you can run static class-methods from an object in Java. In effect, object.staticMethod(); gets translated into something like object.getClass().staticMethod();. AFAIK, no other language has this "feature". Is there any reason behind this madness?