Getting Started with Javascript
Some resources for basic javascript
HTML Dom Events reread: (http://www.w3schools.com/js/js_performance.asp)
Sort Ascending
var points = [40, 100, 1, 5, 25, 10];
points.sort(function(a, b){return a-b});
Sort Descending
var points = [40, 100, 1, 5, 25, 10];
points.sort(function(a, b){return b-a});
The Compare Function: function(a, b){return a-b}
The purpose of the compare function is to define an alternative sort order.
The compare function should return a negative, zero, or positive value, depending on the arguments:
function(a, b){return a-b}
When the sort() function compares two values, it sends the values to the compare function, and sorts the values according to the returned (negative, zero, positive) value.
Example:
When comparing 40 and 100, the sort() method calls the compare function(40,100).
The function calculates 40-100, and returns -60 (a negative value).
The sort function will sort 40 as a value lower than 100.