How can I use setTimeout() in a Backbone model? I have the next code:
var ContentModel = Backbone.Model.extend({
URL: "http://localhost/example.php",
requestType: "POST",
dataType: "json",
data: "", //Set the value outside the model
startSend: function (Data) {
//
},
reply: function (Data) {
var dataJson = eval(Data);
console.log(dataJson);
setTimeout(this.ajaxRequest(),4000);
},
problems: function (Data) {
//
},
ajaxRequest: function () {
$.ajax({
async:true,
type: this.requestType,
dataType: this.dataType,
url: this.URL,
data: this.data,
beforeSend:this.startSend,
success: this.reply,
timeout:4000,
error:this.problems
});
}
});
Alternatively I have tried:
setTimeout(function(){
//ajax code
},4000);
But the result is the same. setTimeout() don't work. The request only run once.
How can I use setTimeout() in a Backbone model? I have the next code:
var ContentModel = Backbone.Model.extend({
URL: "http://localhost/example.php",
requestType: "POST",
dataType: "json",
data: "", //Set the value outside the model
startSend: function (Data) {
//
},
reply: function (Data) {
var dataJson = eval(Data);
console.log(dataJson);
setTimeout(this.ajaxRequest(),4000);
},
problems: function (Data) {
//
},
ajaxRequest: function () {
$.ajax({
async:true,
type: this.requestType,
dataType: this.dataType,
url: this.URL,
data: this.data,
beforeSend:this.startSend,
success: this.reply,
timeout:4000,
error:this.problems
});
}
});
Alternatively I have tried:
setTimeout(function(){
//ajax code
},4000);
But the result is the same. setTimeout() don't work. The request only run once.
Share Improve this question edited May 9, 2013 at 12:49 user2181408 asked Jan 7, 2013 at 23:55 vicenrelevicenrele 9713 gold badges19 silver badges38 bronze badges3 Answers
Reset to default 15A couple of things are amiss. First off, this line:
setTimeout(this.ajaxRequest(),4000);
Should be:
setTimeout(this.ajaxRequest, 4000);
The first line of code executes the ajaxRequest function and passes the result (which is undefined) to setTimeout. That means the ajaxRequest function will execute once, but too soon. The latter line does what you want, which is to pass the function itself to setTimeout, and ajaxRequest will be called 4 seconds later.
But that's not quite enough. When the ajaxRequest function is executed, the value of this context is incorrect. When you called setTimeout, the context of the callback is set to window. You can verify this by console.log(this) in the callback function.
To fix it, you need to bind the context of the function. Since you're using Backbone, you've also got underscore.js already loaded. Using _.bind oughta do it:
setTimeout(_.bind(this.ajaxRequest, this), 4000);
Edit:
Come to think of it, there might be another problem. When the ajax call succeeds or fails, the reply or problems functions may suffer from the same loss of context as ajaxRequest did. But if there is, it's easily fixed.
Instead of calling _.bind on those too, the simplest way is to call _.bindAll in your Backbone model constructor.
initialize: function() {
_.bindAll(this, 'ajaxRequest', 'reply', 'problems');
}
When you call _.bindAll, underscore guarantees that every time any of the listed methods of your model is called, the this context variable points to the model itself, unless specifically bound to something else.
You don't need to do anything special to use setTimeout with backbone. Check the scope of this in your reply function. My guess it that this.ajaxRequest() isn't in scope.
You have to use setInverval instead.
setInterval(this.ajaxRequest, 4000);
setTimeout Triggers the function once.
setInterval Triggers each n ms.
var interval = setInterval(this.ajaxRequest, 4000);
clearInterval used to clear setInterval.
clearInterval(interval);
Or pass the context parameter on your ajax:
$.ajax({
...
context: this,
...
});