Javascript: arrays, object, sorting and prototypes?

I made an array of objects and was able to sort by one of the properties of the objects (see bottom code). But I hardcoded which property to sort by (in this case "name"). How would I be able to pass to the sort method the property I am looking to sort by? I tried tmpArray.sort(function(a, b, sortBy) but got a no soup for you response. I know I can modify the array object with

array.prototype.thing = function(){ alert("hello world"); } 

But is is possible for me to modify an existing method, like array.sort? Thanks.

$(document).ready(function(){

    $(".sort").click(function() { 

    var tmpArray = new Array;

    for (i开发者_如何学编程=0; i<5; i++) { 

        var tmpObject = new Object;
        switch(i) { 

            case 0 : 
                tmpObject.name = "Amy";
                tmpObject.rank = 1;
                tmpObject.priority = 3;
                tmpObject.item = "Blue Item";
                break;

            case 1 :
                tmpObject.name = "Jen";
                tmpObject.rank = 2;
                tmpObject.priority = 0;
                tmpObject.item = "Red Item";
                break;

            case 2 :
                tmpObject.name = "Mike";
                tmpObject.rank = 3;
                tmpObject.priority = 2;
                tmpObject.item = "Green Item";
                break;

            case 3 :
                tmpObject.name = "Raul";
                tmpObject.rank = 4;
                tmpObject.priority = 2;
                tmpObject.item = "Yellow Item";
                break;                      

                            case 4 :
                tmpObject.name = "Lola";
                tmpObject.rank = 5;
                tmpObject.priority = 1;
                tmpObject.item = "Blue Item";
                break;                      

        }

        tmpArray.push(tmpObject); 
    }

    tmpArray.sort(function(a, b) {
             var nameA=a.name.toLowerCase(), nameB=b.name.toLowerCase()

        if (nameA < nameB) //sort string ascending
            return -1
        if (nameA > nameB)
            return 1

        return 0 //default return value (no sorting)
        });

        console.log(tmpArray);

    });

});

Quick example, something like this should work. arr being the Array to sort, key being the Object key to use. Mind you, this is only one level deep sorting.

var arr = [
    {"one" : Math.random(), "two" : Math.random(), "id" : "First"},
    {"one" : Math.random(), "two" : Math.random(), "id" : "Second"},
    {"one" : Math.random(), "two" : Math.random(), "id" : "Third"}
];

var oSort = function (arr, key) {
    arr.sort(function(a, b) {
        a = a[key], b = b[key];
        return a > b ? 1 : a < b ? -1 : 0;
    });
};

oSort(arr, 'two');

http://jsfiddle.net/XwswP/

Edit to answer

But is is possible for me to modify an existing method, like array.sort? Thanks.

Yes it's possible, but don't do that. If you wanted to overwrite it, you could do
Array.prototype.sort = function() { ...

You can write a[someString] to get the property named in the someString variable.

Your sort seems to be working fine here:

http://jsfiddle.net/maniator/2nFYN/