javascript global variable not working with external js file

Question

I have declared the following variable outside of an external js file because part of it is generated server side.

<script type="text/javascript">
     var images=new Array(<%= Master.slideshowArray %>);
</script>

For some reason, by removing this from the external js file (below) the slideshow no longer works... I am guessing I've made an error declaring it as a global variable or perhaps there's something else I need to declare globally... Any ideas?

var nextimage=0;

doSlideshow();

function doSlideshow()
{
    if($('.backgroundImage').length!=0)
    {
        $('.backgroundImage').fadeOut(500,function(){slideshowFadeIn();$(this).remove();});
    }
    else
    {
        slideshowFadeIn();
    }
}

function slideshowFadeIn()
{
    if(nextimage>=images.length) 
        nextimage=0;

    $('.homeLeadContent').prepend($('<img class="backgroundImage" src="'+images[nextimage++]+'" style="display:none;">').fadeIn(500,function() {
        setTimeout(doSlideshow,1000);
    }));
}

DOM already defines a global variable called images. Have your tried a different name? — RoToRa
– RoToRa, Commented Mar 8, 2011 at 9:50
What does the generated inline script tag look like? Are you sure there aren't syntax errors causing that script tag to fail to execute? — Nathan Ostgard
– Nathan Ostgard, Commented Mar 8, 2011 at 10:59

typo.pl · Accepted Answer · 2011-03-08 09:45:52Z

1

Does the script tag for the external js file come before the var images=... inline script tag?

Browsers execute code in the order that they see them, so if the external js file is seen first, it'll execute the doSlideShow() function which may call the slideshowFadeIn() which would try and references a non-existent-at-that-point images variable.

answered Mar 8, 2011 at 9:45

typo.pl

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5 Comments

Tom Over a year ago

Nope... the inline script tag with the var images comes first, then the external file...

typo.pl Over a year ago

If you do alert(typeof(images)); on the line after var images=..., do you get an alert showing object or something kosher, i.e. you don't want to see 'undefined'?

Tom Over a year ago

So if I see 'undefined' (which I did), what would be the next thing to do...?

typo.pl Over a year ago

Then there's something wrong with your var images=... line. You should be able to extract that particular line into a local HTML file and debug using FireBug or some other JavaScript debugger. If you showed that line to us, someone might point out the problem.

Tom Over a year ago

Firebug revealed that I had a typo in the link to the external file... all else is good now - declared as object! thanks

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