How to set context 'this' to custom object inside function?

Consider code like this:

externa开发者_运维知识库l_function = function() {
    $(this).something2();
}

$('.someclass').live('click', function() {

    $(this).something1();
    external_function(); // wrong way

});

I can add a new method:

external_function = function() {
    $(this).something2();
}

$('.someclass').live('click', function() {

    $(this).something1();
    this.external_function = external_function;
    this.external_function(); // this will work

});

but it seems having overhead to me. Is there a perfect and safe way run external_function with custom context?

You should read about apply and call: https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function/call