use ajax request json output in settimeout function

Question

I have a var in jquery after a request like

         type: 'POST',
     data: data,
     cache: false,
     success: function (data) {
         var json = jQuery.parseJSON(data);

I'm trying to use timeout to fire the function below after five seconds.

        $("#a" + json.id).fadeOut(300);

At the moment I'm doing

          setTimeout('$("#a" + json.id).fadeOut(300)', 500);

but it doesn't seem to work

When you pass a String to setTimeout() or setInterval(), it'll be evaluated in the global scope, where json isn't available. — Jonathan Lonowski
– Jonathan Lonowski, Commented Jan 19, 2014 at 3:52

Andrew De Forest · Accepted Answer · 2014-01-19 03:47:03Z

3

setTimeout takes a function and a number as a parameter, try this:

setTimeout(function() {
    $("#a" + json.id).fadeOut(300);
}, 500);

answered Jan 19, 2014 at 3:47

Andrew De Forest

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2 Comments

Kwaasi Djin Over a year ago

Firebug says typeError: ("#a" + json.id).fadeOut is not a function

Andrew De Forest Over a year ago

See my edit, I forgot to put a $ in front of ("#a" + json.id).fadeOut(300)

Schien · Accepted Answer · 2014-01-19 05:35:58Z

0

Not sure if the value of json.id changes by the time the timeout callback is called.

Consider the following example:

for (var i=0;i<10;i++){
  setTimeout(function(){console.log(i)},500);
}

The callback function sees i=10 because that's the value of i by the time the function is invoked. You can do a pre-binding by using closure:

var f=function(id){
  setTimeout(function(){console.log(id);},500);
}

for (var i=0;i<10;i++) f(i);

Now that you see how closure and pre-binding work, here's a more robust solution to your question:

var f=function(id){
  setTimeout(function(){$('#a'+id).fadeOut(300);},500);
}

f(json.id);

answered Jan 19, 2014 at 5:35

Schien

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Comments

lorefnon · Accepted Answer · 2014-01-19 05:42:48Z

0

Your code doesn't work because the String is eval'ed in global context. So for it to work you can make json global (remove the var).

Also, while I am not sure where you are calling the setTimeout from, but assuming it is inside the callback, you can alternatively make the id a part of the string :


setTimeout('$("#a'+json.id+'").fadeOut(300)', 500);

But certainly a better option is to avoid eval and globals at all costs (checkout Eval is evil and Why global state is the devil for an elaborate explaination) and pass in a closure :


setTimeout(function(){ $("#a" + json.id).fadeOut(300); }, 500);

answered Jan 19, 2014 at 5:42

lorefnon

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