Question

I’m trying to find out how to extend JavaScript with some of my own methods similar to toLowerCase()

Say I wanted a capitalize() or addUnderscores(), really whatever. I’m assuming there is a way to extend or overwrite existing ones.

Also is there a way to do it with jQuery?

Answer 1

Not with jQuery. Just extend the prototype of the specific type you need…

if (!String.prototype.capitalize) {
    String.prototype.capitalize = function() {
        return this.toUpperCase();
    }
}

'foobar'.capitalize(); // 'FOOBAR'

In the function, this will be the string on which you called the method.