What does this script do?

[yukon4]

Here's a really simple question - what does this script below do? Also, is there such a tool where you enter some script and it gets "translated" for you? ie, you can determine what a given piece of script will do? Thank you!

<script language="JavaScript" type="text/JavaScript">
<!--
function MM_findObj(n, d) { //v4.01
var p,i,x; if(!d) d=document;
if((p=n.indexOf("?"))>0&&parent.frames.length) {
d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++)
x=d.forms[i][n];
for(i=0;!x&&d.layers&&i<d.layers.length;i++)
x=MM_findObj(n,d.layers[i].document);
if(!x && d.getElementById) x=d.getElementById(n); return x;
}
//-->
</script>

[yukon4]

Thank you Dave! I'm ashamed to say that I'm not quite sure what your explanation means? Could you "translate" further, all the way into plain English?! Sorry about that and thank you again!