Javascript undifined variable after loop

Question

I have a countdown script that redirects to a file. It has a loop in it and the variable gets undifined when it ran once.

How can i keep the url variable to hold its value?

        <a id="" onClick="doTimer('http://www.domain.com/downloadfile.php?photo=foo.jpg')" href="#"><button id="download">Download this photo</button></a>

        var timer_is_on=0;
        var countdownfrom=5
        var currentsecond=document.getElementById('countdown').innerHTML=countdownfrom+1 

        function countredirect(url)
        { 
            if (currentsecond!=1)
            {
                currentsecond-=1 
                document.getElementById('countdown').innerHTML = currentsecond;
            } 
            else
            { 
                window.location=url 
                return 
            } 
            setTimeout("countredirect()",1000) 
        }
        function doTimer(url)
        {
            if(!timer_is_on)
            {
                document.getElementById('download').innerHTML="Your download starts in <span id=\"countdown\"></span>seconds";
                timer_is_on=1;
                countredirect(url) 
            }
        }

Never pass a string to setInterval() or setTimeout(). Doing so is as bad as using eval() and it results in unreadable and possibly insecure code as soon as you use variables since you need to insert them into the string instead of passing the actual variable. The proper solution is setInterval(function() { /* your code *) }, msecs);. The same applies to setTimeout(). If you just want to call a single function without any arguments, you can also pass the function name directly: setInterval(someFunction, msecs); (note that there are no () behind the function name) — ThiefMaster
– ThiefMaster, Commented Apr 19, 2012 at 11:09

Felix Kling · Accepted Answer · 2012-04-19 11:10:11Z

5

setTimeout("countredirect()",1000)

You are not passing any argument to your countredirect function.

Passing strings to setTimeout and setInterval is generally a bad idea (gives you all sorts of scope problems). Pass a function instead:

setTimeout(function() {
    countredirect(url);
}, 1000);

In newer browsers (or with shim) you can also use .bind() ^[MDN] (bind returns a new function):

setTimeout(countredirect.bind(null, url), 1000);

answered Apr 19, 2012 at 11:10

Felix Kling

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Alexander Pavlov · Accepted Answer · 2012-04-19 11:11:46Z

0

An alternative approach to re-scheduling your function:

setTimeout(countredirect.bind(null, url), 1000);

answered Apr 19, 2012 at 11:11

Alexander Pavlov

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