Consider the following code:
MyClass.prototype.my_func = function () {
this.x = 10;
$.ajax({
// ...
success: function (data) {
You can make usage of Function.prototype.bind
for that:
MyClass.prototype.my_func = function () {
this.x = 10;
$.ajax({
// ...
success: function (data) {
alert(this.x);
}.bind(this);
});
}
Now the parent context variable is also bound to the anonymous function.
the this
syntax usually refers to the object, not a function. In your case, this
refers to MyClass.
If you're using the variable in the object, you probably forgot to define x
in MyClass
.
If you're using the variable within the function ONLY I'd define my variables using the var
syntax. Variables defined within a function are destroyed when a function ends.
MyClass.prototype.my_func = function () {
var x = 10;
$.ajax({
// ...
success: function (data) {
alert(x);
}
});
}
The closure will have access to all objects defined in its parent's context. So if we have:
function() {
var x = 10;
}
Then this is valid:
function() {
var x = 10;
(function() {
alert(2*x); // 20
}())
}
Therefore, when you define var _this = this
you have merely defined a new variable in the parent's context that is available within the closure. See question #4371333 for more information on this "pattern."
This may look like the ugly solution for you and there are some walkarounds (such as using bind() method to change the context), but this is the best solution I know of.
Alternatively you can change it to:
var self = this;
or give it more meaningful name, but it would be better (in this case) not to change the context, as you may need it some day.