How to stop mouse right click on a webpage

There are many cases when we don't allow users to see our source code.Enabling source code by right click provide option to users to load images of our site and see logic we you used to make your website.You can disable right click using java script paste the following code on your head section and see the magic
Paste this code on header section

<SCRIPT LANGUAGE="JavaScript">  
<!-- Disable  
function disableselect(e){  
return false  
}  

function reEnable(){  
return true  
}  

//if IE4+  
document.onselectstart=new Function ("return false")  
document.oncontextmenu=new Function ("return false")  
//if NS6  
if (window.sidebar){  
document.onmousedown=disableselect  
document.onclick=reEnable  
}  
//-->  
</script>