var content = new Array("books", "materials", "itech", "projnext",
			"teaching", "other");
var contentBG = new Array();
contentBG["books"]     = "#ffeeee";
contentBG["materials"] = "#f0f0ee";
contentBG["itech"]     = "#eeffee";
contentBG["projnext"]  = "#eeffee";
contentBG["teaching"]  = "#eef0f0";
contentBG["other"]     = "#eeeeff";

var imageFiles = new Array();
imageFiles["books"] = "rotate_images/books.jpg";
imageFiles["materials"] = "rotate_images/catsfasching.jpg";
imageFiles["itech"] = "rotate_images/glrfasching.jpg";
imageFiles["projnext"] = "rotate_images/glrnextsgn.jpg";
imageFiles["teaching"] = "rotate_images/redfasching.jpg";
imageFiles["other"] = "rotate_images/silhouettemt.jpg";

var imageObj = new Array();

function setcontent( name ) {
    // set the main content window contents, update the button
    //    background and lower image
    var item = document.getElementById( "nav" + name );
    var imag = document.getElementById( "nav" + name + "img" );
    var pict = document.getElementById( "contentimage" );
    var text = document.getElementById( name + "text" );

    item.style.backgroundImage = 'url("struct_images/horiztab_topwhitebg.gif")';
    item.style.borderRight = "#eeeeee solid 1px";

    imag.src = "struct_images/horiztab_botwhitebg.gif";

    text.style.position = "relative";
    text.style.left = "0px";
    text.style.top = "0px";

    pict.src = imageObj[name].src;

    for ( var i=0; i<content.length; i++ ) {
	if ( content[i] != name ) {
	    var oitm = document.getElementById( "nav" + content[i] );
	    var oimg = document.getElementById( "nav" + content[i] + "img" );
	    var otxt = document.getElementById( content[i] + "text" );
	    oitm.style.backgroundImage = 'url("struct_images/horiztab_topgreybg.gif")';
	    oimg.src = "struct_images/horiztab_botgreybg.gif";
	    oitm.style.borderRight = "#adadad solid 1px"

	    otxt.style.position = "absolute";
	    otxt.style.left = "-1500px";
	    otxt.style.top = "-1500px";
	}
    }
}

// preload images
function preload() {
    for ( var i=0; i<content.length; i++ ) {
        imageObj[content[i]] = new Image(250,188);
        imageObj[content[i]].src = imageFiles[content[i]];
    }
}