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JavaScript jQuery Basics (2014) Creating a Mobile Drop Down Menu Perform: Part 1

Björn Norén
Björn Norén
9,569 Points
Posted by Björn Norén
Björn Norén
9,569 Points

A question about "this"

Hi, I just wonder what "this" is in this situation. I tried to prompt it and got [object Object].

Is it pointing to the a-tag in the menu-id? I ask cause I feel it's time for me grasp the concept of this and understand its functions ... Thanks! 

var $select = $("<select></select>");
$("#menu").append($select);


$("#menu a").each(function(){
    var $anchor = $(this);
    var $option = $("<option></option>");

    $option.val($anchor.attr("href"));

    $option.text($anchor.text());

    $select.append($option);

    var message = prompt($anchor);
});

2 Answers

Daniel Gonzalez
Daniel Gonzalez
22,105 Points
Daniel Gonzalez
Daniel Gonzalez
22,105 Points

Hi,

Below is a great TeamTreehouse workshop about the use of "this" in javascript.

https://teamtreehouse.com/library/understanding-this-in-javascript

Angelica Hart Lindh
Angelica Hart Lindh
19,465 Points
Angelica Hart Lindh
Angelica Hart Lindh
19,465 Points

Hi Björn,

Daniel pointed out a great workshop from Treehouse on 'this' in JavaScript.

I wanted to explain 'this' in your context also, perhaps it will help. The keyword $(this) within the $("#menu a").each(function(){}); relates to the current subject being passed to the iterator, in this case it is a DOM element <a></a> tag.

The reason you are having [object Object] returned in your prompt is because the jQuery $(this) returns the DOM element as a jQuery object so to reference it in your prompt you would do:

var message = prompt($anchor[0]);

However, jQuery is used to help with DOM manipulation and you don't necessarily need to use the jQuery $(this). For example:

$(this)[0] === this;

So in your code

prompt($(this)[0]) 
// Same as 
prompt(this);