help with syntax

[JimHo]

I need a little help with syntax in a function. I am trying to use a variable in the getelementbyid method as follows:

function update(series)
{
var icon =eval(series +"icon");

document.getElementById( icon ).style.MozOpacity=1;
document.getElementById( icon ).filters.alpha.opacity=100;
}

I am trying to define the opaque property of Image1 at runtime based on mouseover events of Image2.

Thanks Jim

[Fotiman]

Remove the eval portion. Assuming series is a string or a number, you can just concatinate them without using eval.

Also, you should probably add a check to make sure the element was found before you try to modify it's properties.

function update(series) 
{ 
 var icon = document.getElementById( series + "icon" ); 
 if(!icon ) return; 
 icon.style.MozOpacity=1; 
 icon.filters.alpha.opacity=100; 
} 

[JimHo]

Thank You. I appreciate your help!

[JimHo]

I must be doing something wrong here

I set up the following to test:

function update(series)
{
var icon = document.getElementById(series + "icon");
icon.filters.alpha.opacity=100;
}

I then checked it in Firefox's Javascript Console, and it choked on the "icon.filters.alpha.opacity=100;" line with an error code - icon has no properties

Any ideas?

[Fotiman]

function update(series)
{
var icon = document.getElementById(series + "icon");
icon.filters.alpha.opacity=100;
}

I then checked it in Firefox's Javascript Console, and it choked on the "icon.filters.alpha.opacity=100;" line with an error code - icon has no properties

1. That's why you should have the check:
if(!icon ) return;
In your case, though, you might use this to debug by doing this:

if(!icon ) 
{ 
 alert('unable to find icon with id: ' + series + 'icon'); 
 return; 
} 

If it gives you the alert, then you must not be searching for the right thing.

2. I could be wrong, but I think filters are an IE only thing. So when you try and modify the filter property of an object, Firefox (and any other non-IE browser for that matter) will probably barf because the property doesn't exist. Maybe you could do something like this to get around it:
if( icon.filters )
{
if( icon.filters.alpha )
{
icon.filters.alpha.opacity=100;
}
}

[JimHo]

Got it thanks!