if (document.images) { 

// talk navigation
var img17on = new Image();
img17on.src = "../images/talk_navi01_on.gif"; 
var img17off = new Image();
img17off.src = "../images/talk_navi01.gif";

var img18on = new Image();
img18on.src = "../images/talk_navi02_on.gif"; 
var img18off = new Image();
img18off.src = "../images/talk_navi02.gif";

var img19on = new Image();
img19on.src = "../images/talk_navi03_on.gif"; 
var img19off = new Image();
img19off.src = "../images/talk_navi03.gif";

var img20on = new Image();
img20on.src = "../images/talk_navi04_on.gif"; 
var img20off = new Image();
img20off.src = "../images/talk_navi04.gif";

} 


function On(name) { 

if (document.images) { 
document.images[name].src = eval(name + 'on.src'); 
} 

} 


function Off(name) { 

if (document.images) { 
document.images[name].src = eval(name + 'off.src'); 
} 

}