Javascript context menu click event/detection - filter paste content

Question

Scenario: I'm trying to intercept paste events inside a textarea/input text, and filter the content being pasted.

Webkit/IE are handled rather well, as I can attach code to the onpaste event, and then read from the clipboard what is being pasted. Plenty of examples around.

Gecko is trickier, because as far as I know it isn't possible to read the clipboard content on Firefox (unless somebody knows a workaround for that?)
I just use the input swap trick for that.

Opera is being annoying tho. I can trap CTRL+V and SHIFT+INS, but there's no onpaste event.
Not to mention any sort of clipboard interaction, apparently.

So, my question is:

Can I detect if the user clicked on paste in the context menu on Opera? Is there any other way to detect the event?

EDIT:

Thanks everybody for the answers - they all add a good input, even if there's no definitive solution.
Having to choose, I'll pick the only one that tried to address the original question, and that would probably work if it wasn't too much of an hack to even try.

Notes for those that have my same problem (input filtering):

• it is possible to capture content being dragged: mouseup + setTimeout does the trick everywhere almost perfectly.
• without flash, there is probably no solution bar polling. Even with flash, it's not a completely solid solution either. Too much effort to support 100% of the cases.

Answer 1

I ran into this last year. In short, no.

I ended up using an onchange handler and filtering the content after it's already been pasted into the text box.

Answer 2

You can intercept the paste with jQuery using the bind('paste', function() {});, compare string before and after pasting and apply your formatting.

The following was tested in IE7/FF3.6/Chrome/Safari 5

$("#textarea").bind('paste', function(e){ 
    // Do whatever you needed to do with the code here.
});

Live Example http://jsfiddle.net/VSrTg/2/

Edit An approach would be something like this:

$("#textarea").bind('paste', function(e){ 
    var oldText = this.value;
    setTimeout(function() { 
        // Compare oldText to $("#textarea").val() and format accordingly.
    }, 1000);
});

​Edit 2 Given your revisions to your original post, if you're worried about the giant market share that is Opera, you're going to have to monitor the value of your textbox with a setInterval() and compare it against itself for changes.

Ultimately there will always be a way around your script, even the above example is susceptible to simply dragging text from another text box (or the address bar) into it without triggering the paste event defined above.

Answer 3

I would like to point out DOJO menu widget that is creating context menus perfectly in different browsers. http://www.dojotoolkit.org/reference-guide/dijit/Menu.html#dijit-menu

What you can do is that detect paste event in browsers that are supporting it and override context menu in browsers that are not supporting this event like opera.

Once you create your own context menu then you can add copy paste menu item or create context menu similar to the default using css.

Edited Some browsers might not allow us to fetch clipboard content, in this case we can always revert back to flash for borrowing some of its features that are cross browser. See couple of links I posted in comments.

Its complete implementation might have more issues than anticipated but it is possible and we can always give it a try (I will for sure).

Answer 4

The answer to the question is a simple no. The main browsers that have no paste event are recent versions of Opera and Firefox 2. Given that there is no paste event, you need to find an alternative event or set of events to detect a paste from the context menu as it actually happens. You can add handlers for every event there is (I've done this) and you simply get nothing in the relevant browsers when a paste is triggered from the context menu by the user.

This only leaves polling the text input's value regularly, which is not the same thing. You could keep track of keypresses and observe in your polling code that the text input's value has changed by some means other than keyboard input and do a diff, but that's hacky and unreliable.

Answer 5

I use the setTimeout for paste events. But for context menu select nothing seems to work(as stated above). I bind a mousemove to the input's form which fires the update function. Then unbind/bind so they don't stack up.

This handles the context menu select and dragging value to input field.

If your form is small, say with only one input field and the mouse will not land on it after selecting from context menu, bind to the form's parent or document. Sure, it has to wait until the mouse moves but that is the general user action after selecting from context menu.

Works fine.