[inebriate]

its better to use {ldelim} and {rdelim} if you have smarty code you want to use inside, it will act as a normal left and right brace,
ie:

<script language="JavaScript">
<!--
/*
Random Image Script- By JavaScript Kit (http://www.javascriptkit.com) 
Over 400+ free JavaScripts here!
Keep this notice intact please
*/

function random_imglink(){ldelim}
var myimages=new Array()
//specify random images below. You can have as many as you wish
myimages[1]="{$ImagesDir}/ezbail.jpg"
myimages[2]="{$ImagesDir}/swivelclamp.jpg"
myimages[3]="{$ImagesDir}/speaker.jpg"

var ry=Math.floor(Math.random()*myimages.length)
if (ry==0)
ry=1
document.write('<img src="'+myimages[ry]+'">')
{rdelim}
random_imglink()
//-->
</script> 

instead of dealing with the opening and closing literal tags for smarty variables, if its just plain javascript with no smarty inside then just wrap with literal tags