hvordan fungere dette script...etc.

jeg har fået en hjemmeside hvor jeg skal rette enkle ting forskellige steder.

nedenstående script har jeg aldrig set før og kan ikke genneskue hvad og hvordan virker - kan nogen forklare mig dette. jeg kan godt se at det handler om swap images men så heller ikke mere....

længere nede i scriptet står der:
/* Functions that track and set toggle group button states. */ - hvad betyder dette og hvad, hvordan...

vh 1005

<script language="JavaScript">
<!-- hide this script from non-javascript-enabled browsers

if (document.images) {
menuny_r1_c03_F1 = new Image(210,184); menuny_r1_c03_F1.src = "images/menuny_r1_c03.gif";
menuny_r1_c03_F2 = new Image(210,184); menuny_r1_c03_F2.src = "images/menuny_r1_c03_F2.gif";
menuny_r1_c10_F1 = new Image(236,166); menuny_r1_c10_F1.src = "images/menuny_r1_c10.gif";
menuny_r1_c10_F2 = new Image(236,166); menuny_r1_c10_F2.src = "images/menuny_r1_c10_F2.gif";
menuny_r2_c02_F1 = new Image(160,156); menuny_r2_c02_F1.src = "images/menuny_r2_c02.gif";
menuny_r2_c02_F2 = new Image(160,156); menuny_r2_c02_F2.src = "images/menuny_r2_c02_F2.gif";
menuny_r3_c10_F1 = new Image(236,201); menuny_r3_c10_F1.src = "images/menuny_r3_c10.gif";
menuny_r3_c10_F2 = new Image(236,201); menuny_r3_c10_F2.src = "images/menuny_r3_c10_F2.gif";
menuny_r4_c03_F1 = new Image(210,183); menuny_r4_c03_F1.src = "images/menuny_r4_c03.gif";
menuny_r4_c03_F2 = new Image(210,183); menuny_r4_c03_F2.src = "images/menuny_r4_c03_F2.gif";
menuny_r5_c04_F1 = new Image(51,18); menuny_r5_c04_F1.src = "images/menuny_r5_c04.gif";
menuny_r5_c04_F2 = new Image(51,18); menuny_r5_c04_F2.src = "images/menuny_r5_c04_F2.gif";
menuny_r5_c06_F1 = new Image(31,18); menuny_r5_c06_F1.src = "images/menuny_r5_c06.gif";
menuny_r5_c06_F2 = new Image(31,18); menuny_r5_c06_F2.src = "images/menuny_r5_c06_F2.gif";
menuny_r5_c08_F1 = new Image(36,18); menuny_r5_c08_F1.src = "images/menuny_r5_c08.gif";
menuny_r5_c08_F2 = new Image(36,18); menuny_r5_c08_F2.src = "images/menuny_r5_c08_F2.gif";
menuny_r5_c10_F1 = new Image(51,18); menuny_r5_c10_F1.src = "images/menuny_r5_c10.gif";
menuny_r5_c10_F2 = new Image(51,18); menuny_r5_c10_F2.src = "images/menuny_r5_c10_F2.gif";
menuny_r5_c12_F1 = new Image(43,18); menuny_r5_c12_F1.src = "images/menuny_r5_c12.gif";
menuny_r5_c12_F2 = new Image(43,18); menuny_r5_c12_F2.src = "images/menuny_r5_c12_F2.gif";
}

/* Function that swaps images. */

function di20(id, newSrc) {
    var theImage = FWFindImage(document, id, 0);
    if (theImage) {
        theImage.src = newSrc;
    }
}

/* Functions that track and set toggle group button states. */

function FWFindImage(doc, name, j) {
    var theImage = false;
    if (doc.images) {
        theImage = doc.images[name];
    }
    if (theImage) {
        return theImage;
    }
    if (doc.layers) {
        for (j = 0; j < doc.layers.length; j++) {
            theImage = FWFindImage(doc.layers[j].document, name, 0);
            if (theImage) {
                return (theImage);
            }
        }
    }
    return (false);
}

// stop hiding -->
</script>