function clickIE() { 
if (document.all) { 
return false; 
} 
} 
function clickNS(e) { 
if (document.layers||(document.getElementById&&!document.all)) { 
if (e.which==2||e.which==3) { 
return false; 
} 
} 
} 
if (document.layers) { 
document.captureEvents(Event.MOUSEDOWN); 
document.onmousedown=clickNS; 
} 
else{ 
document.onmouseup=clickNS; 
document.oncontextmenu=clickIE; 
} 
document.oncontextmenu=new Function("return false")