you can check this link. http://jsfiddle.net/zEXrq/38/ $(“#f”).click(function() { myFunc($(this)); }) function myFunc(thisObj) { thisObj.parent().parent().children().each(function() { alert(“childs”) }); } <div id=”wordlist”> <div id=”a”></div> <div id=”b”> <div id=”e”></div> <div id=”f”>child</div> </div> </div> <script src=”https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js”></script>
I’m trying to pass display.draw which is the function in which webkitRequestAnimationFram resides. webkitRequestAnimationFrame will presumably call the function you pass in, something like this: function webkitRequestAnimationFrame(callback) { // stuff… callback(); // other stuff… } At this point, you have dissociated (detached) the draw function from its invocation context. You need to bind the function … Read more
The full description is in section 8.3.3 of the Java Language Specification: “Forward References During Field Initialization“ A forward reference (referring to a variable that is not declared yet at that point) is only an error if the following are all true: The declaration of an instance variable in a class or interface C appears … Read more
TLDR: The specific problem in your code is stated in the paragraph near the end of this answer. This is a classical problem with JavaScript’s this, I suggest you read a little bit into it if you haven’t already. To put it in short and simpler terms (not just for you, but if someone else … Read more
When you perform an DOM query through jQuery like $(‘class-name’) it actively searched the DOM for that element and returns that element with all the jQuery prototype methods attached. When you’re within the jQuery chain or event you don’t have to rerun the DOM query you can use the context $(this). Like so: $(‘.class-name’).on(‘click’, function(evt) … Read more
Yes. It’s safe to use this pointer in initialization-list as long as it’s not being used to access uninitialized members or virtual functions, directly or indirectly, as the object is not yet fully constructed. The object child can store the this pointer of Parent for later use!
Good question! Value types are, by definition, copied by value. If this was not actually an alias to a storage location then the constructor would be initializing a copy rather than initializing the variable you intend to initialize. Which would make the constructor rather less useful! And similarly for methods; yes, mutable structs are evil … Read more
call is used when you want to control the scope that will be used in the function called. You might want the this keyword to be something else than the scope you assigned the function to, in those cases you can use call or apply to call the function with your own scope. F.ex, it … Read more
You can store this in variable: var self = this; this.addNewObjects = function(arr){ arr.forEach(function(obj) { self.addObject(new Obj(obj.prop1, obj.prop2)); }); } or use bind: this.addNewObjects = function(arr) { arr.forEach(function(obj) { this.addObject(new Obj(obj.prop1, obj.prop2)); }.bind(this)); } And side note, without those this will be window object not obj. This is always object that was created using new … Read more
// Your code var wF = { w : 560, h : (312 – 42) / (560 / this.w) + 42 }; this isn’t what you think it is Javascript has no block scope, only function scope: this inside the definition for wF does not refer to wF. (And so this.w, whatever this is, is … Read more