how to map an array with uppercase function in javascript?

Check out JavaScript Array.map for info on the official JavaScript map function. You can play around with the sample there to see how the function works. Try copying this into the example box:

var array = ['dom', 'lun', 'mar', 'mer', 'gio', 'ven', 'sab'];
var uppers = array.map(function(x) { return x.toUpperCase(); });
console.log(uppers);

And it will print:

DOM,LUN,MAR,MER,GIO,VEN,SAB

You can use $.map() in order to apply String.toUpperCase() (or String.toLocaleUpperCase(), if appropriate) to your array items:

var upperCasedArray = $.map(array, String.toUpperCase);

Note that $.map() builds a new array. If you want to modify your existing array in-place, you can use $.each() with an anonymous function:

$.each(array, function(index, item) {
    array[index] = item.toUpperCase();
});

Update: As afanasy rightfully points out in the comments below, mapping String.toUpperCase directly will only work in Gecko-based browsers.

To support the other browsers, you can provide your own function:

var upperCasedArray = $.map(array, function(item, index) {
    return item.toUpperCase();
});

This may be an overkill but you can also do

var upperCaseArray = array.map(String.prototype.toUpperCase.call.bind(String.prototype.toUpperCase));