if (document.images) {     

            img1ad = new Image(); img1ad.src = "graphics/1200.jpg"; 
            img2ad = new Image(); img2ad.src = "graphics/140f.jpg";    
            img3ad = new Image(); img3ad.src = "graphics/1100.jpg"; 
	    img4ad = new Image(); img4ad.src = "graphics/600.jpg"; 
	    img5ad = new Image(); img5ad.src = "graphics/1400.jpg"; 
	    img6ad = new Image(); img6ad.src = "graphics/58c.jpg"; 
	    img7ad = new Image(); img7ad.src = "graphics/580b.jpg"; 
	    img8ad = new Image(); img8ad.src = "graphics/500m.jpg"; 
	    img9ad = new Image(); img9ad.src = "graphics/700d.jpg"; 
	    img10ad = new Image(); img10ad.src = "graphics/400.jpg"; 
	    img11ad = new Image(); img11ad.src = "graphics/640m.jpg"; 
	    img12ad = new Image(); img12ad.src = "graphics/740m.jpg"; 
	    img13ad = new Image(); img13ad.src = "graphics/401h.jpg"; 
	    img14ad = new Image(); img14ad.src = "graphics/840fd.jpg"; 
	    img15ad = new Image(); img15ad.src = "graphics/pd1000.jpg"; 
	    img16ad = new Image(); img16ad.src = "graphics/ps1180.jpg"; 
	    img17ad = new Image(); img17ad.src = "graphics/te1600.jpg"; 
	    img18ad = new Image(); img18ad.src = "graphics/se1600-4.jpg"; 
	    img19ad = new Image(); img19ad.src = "graphics/d11000.jpg"; 
	    img20ad = new Image(); img20ad.src = "graphics/d22000.jpg"; 
	    img21ad = new Image(); img21ad.src = "graphics/ss1180.jpg"; 
	    img22ad = new Image(); img22ad.src = "graphics/ss1135.jpg"; 
	    img23ad = new Image(); img23ad.src = "graphics/te1400.jpg"; 
	    img24ad = new Image(); img24ad.src = "graphics/ss1190.jpg"; 
	    img25ad = new Image(); img25ad.src = "graphics/cd1000.jpg"; 
	    img26ad = new Image(); img26ad.src = "graphics/ct800.jpg"; 
	    img27ad = new Image(); img27ad.src = "graphics/400.jpg"; 
	    img28ad = new Image(); img28ad.src = "graphics/840.jpg"; 
	    img29ad = new Image(); img29ad.src = "graphics/mod880.jpg"; 
	    img30ad = new Image(); img30ad.src = "graphics/mod883.jpg"; 
	    img31ad = new Image(); img31ad.src = "graphics/mod890.jpg"; 
         }

function imgOn(imgName) {
        if (document.images) {
            document["common"].src = eval(imgName + "ad.src");
        }
}

function imgOff(imgName) {
        if (document.images) {
            document["common"].src = "graphics/1200.jpg";
        }
}