how to disable copy paste in website code example

Example: disable copy text from a website

<script type="text/JavaScript">
//courtesy of BoogieJack.com
function killCopy(e){
return false
}
function reEnable(){
return true
}
document.onselectstart=new Function ("return false")
if (window.sidebar){
document.onmousedown=killCopy
document.onclick=reEnable
}
</script>