function click() {
if (event.button==2||event.button==3) {
 oncontextmenu='return false';
  }
}
document.onmousedown=click
document.oncontextmenu = new Function("return false;")

function disabletext(e){
return false
}

function reEnable(){
return true
}

//if the browser is IE4+
document.onselectstart=new Function ("return false")

//if the browser is NS6
if (window.sidebar){
document.onmousedown=disabletext
document.onclick=reEnable
}