Stop User from using "Print Scrn" / "Printscreen" key of the Keyboard for any Web Page

I hate the "it's not possible" sentence. Here's all solutions combined to help you:

1- You can grab the solution from Haluk:

<script type="text/javascript"> $(document).ready(function() {
    $(window).keyup(function(e){
      if(e.keyCode == 44){
        $("body").hide();
      }

    }); }); 
</script>

HOWEVER, you hide body, but's already "printed" to clipboard. You can fire another event that copy some text to your clipboard, as you can see on this answer "Edit as of 2016" Click button copy to clipboard using jQuery , it's something like this:

function copyToClipboard() {
  // Create a "hidden" input
  var aux = document.createElement("input");
  // Assign it the value of the specified element
  aux.setAttribute("value", "Você não pode mais dar printscreen. Isto faz parte da nova medida de segurança do sistema.");
  // Append it to the body
  document.body.appendChild(aux);
  // Highlight its content
  aux.select();
  // Copy the highlighted text
  document.execCommand("copy");
  // Remove it from the body
  document.body.removeChild(aux);
  alert("Print screen desabilitado.");
}

$(window).keyup(function(e){
  if(e.keyCode == 44){
    copyToClipboard();
  }
}); 

This will block a part of your problem. If user focus on another object outside this windows he will be able to take screenshots. **But there's another solution to that as well, simply disable the hole body when window get's unfocused. Full solution, from your dear brazillian friend:

function copyToClipboard() {
  // Create a "hidden" input
  var aux = document.createElement("input");
  // Assign it the value of the specified element
  aux.setAttribute("value", "Você não pode mais dar printscreen. Isto faz parte da nova medida de segurança do sistema.");
  // Append it to the body
  document.body.appendChild(aux);
  // Highlight its content
  aux.select();
  // Copy the highlighted text
  document.execCommand("copy");
  // Remove it from the body
  document.body.removeChild(aux);
  alert("Print screen desabilitado.");
}

$(window).keyup(function(e){
  if(e.keyCode == 44){
    copyToClipboard();
  }
}); 

$(window).focus(function() {
  $("body").show();
}).blur(function() {
  $("body").hide();
});

Here's the example working:

This is not possible.

You can't disable screen grabbing from the Web browser, it would only be possible by installing additional software on the user's PC.

There are some IRM (Information Rights Management) tools available that do that e.g. by protecting Windows/DirectX API calls and also monitoring video memory such as Oracle IRM or such as Microsoft's IRM technology.

Especially the latter might be of interest as there is also a Rights Management Add-on for Internet Explorer.

But as other already said, any IRM/DRM technology is controversy and you should understand that it most often will limit or annoy your users.

Thankfully, this outrageous idea is not possible to implement reliably, neither the "disable screen grab" part nor the "disable user's Firefox extensions" one. And even if it were, as @kbok points out in his comment above, you don't have a right to do this.

The only way to protect your content online is copyright laws - mentioning those is often enough to scare people away from misusing it! - or not showing it at all.

Try this

$(document).keyup(function(e){
  if(e.keyCode == 44) return false;
});

Hope it works