[jQuery] use .filter(':visible') to replace $('#id:visible')

Sometimes we will use

$('div:visible') // Does not use querySelectorAll()

to select something is visible, but it dose not utilize querySelectorAll()

so we can use

$('div').filter(':visible') // Uses it

to get high performance

See Also

http://tutorialzine.com/2011/06/15-powerful-jquery-tips-and-tricks-for-developers/

[JavaScript] Show output in a new window

[JavaScript] remove all duplicate element from array 刪除陣列中重複的元素

jQuery的unique只支援DOM元素, 所以寫一個來支援Array的

jQuery.unique() only support DOM elements, so we need a function to do unique.

	Array.prototype.unique = function () {
	var arrVal = this;
	var uniqueArr = [];
	for (var i = arrVal.length; i--; ) {
	var val = arrVal[i];
	if ($.inArray(val, uniqueArr) === -1) {
	uniqueArr.unshift(val);
	}
	}
	return uniqueArr;
	}

view raw unique.js hosted with ❤ by GitHub

See also : http://www.devcurry.com/2010/04/remove-duplicate-elements-from-array.html