Passing a variable to setIntervall function

Question

i am calling a jQuery plugin every 5 seconds with the following code

    var now = new Date();

    setInterval('$("#id").myplugin(now)', 1000);

The Plugin looks like this so far:

    (function( $ ){
    $.fn.myplugin = function(now) {
        return this.each(function() {
            alert(now.getTime());
        });
    }
   })( jQuery );

However I get the error:

Uncaught ReferenceError: now is not defined
plugins.js:30 Uncaught TypeError: Cannot call method 'getTime' of undefined

So it looks as if the now time object doenst get passed to the plugin function and is not even defined in the setInterval method. I could probably call var now = new Date(); every time in the plugin function ... but I want to know, why it doenst work like that and how to make it work ;). thx alot.

score 5 · Accepted Answer · edited May 23 '17 at 11:55

5

Use a function like this:

var now = new Date();

setInterval(function() {
    $("#id").myplugin(now);
}, 1000);

This way, the so-called scope of now is set to the function in which you call setInterval. Otherwise, it is just the global object (window) you're referring to, which doesn't have a now.

Secondly, passing a string works like eval(), which is unsafe and slow: Why is eval unsafe in javascript?.

edited May 23 '17 at 11:55

Community

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1

answered Jun 01 '11 at 20:15

pimvdb

151,816
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2

This is exactly the way to do it. NEVER pass `setInterval` a string - always pass it a function. – Chris Baker Jun 01 '11 at 20:16

score 1 · Answer 2 · answered Jun 01 '11 at 20:16

1

Use this instead:

setInterval(function(){$("#id").myplugin(now)}, 1000);

answered Jun 01 '11 at 20:16

rahim asgari

12,197
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Passing a variable to setIntervall function

2 Answers2