var darkened_pics = new Array();var lighted_pics = new Array();function preloadButtonSet(num,dark,light) { darkened_pics[num] = new Image(); darkened_pics[num].src = dark; lighted_pics[num] = new Image(); lighted_pics[num].src = light;}preloadButtonSet(0,"Images/author_OFF.gif","Images/author_ON.gif");preloadButtonSet(1,"Images/reviews_OFF.gif","Images/reviews_ON.gif");preloadButtonSet(2,"Images/products_OFF.gif","Images/products_ON.gif");preloadButtonSet(3,"Images/publishers_OFF.gif","Images/publishers_ON.gif");function lighten(num) { if (document.images)  eval("document.button"+num+".src = lighted_pics["+num+"].src;"); return false;}function darken(num) { if (document.images)  eval("document.button"+num+".src = darkened_pics["+num+"].src;"); return false;}