verify = "NOT ALLOWED"; 

fv = parseInt(navigator.appVersion) 

fns = navigator.appName=="Netscape" 

fie = navigator.appName=="Microsoft Internet Explorer" 

function explore(e) { 

if (fns && e.which > 1){ 

alert(verify) 

return false 

} else if (fie && (event.button >1)) { 

alert(verify) 

return false; 

} 

} 
document.onmousedown = explore; 
if (document.layers) window.captureEvents(Event.MOUSEDOWN); 
if (fns && fv<5) window.onmousedown = explore;