limit how many characters can be pasted in textarea

Question

Is it possible to detect how many characters are being pasted into a HTML textarea, and cancel the paste if beyond a limit?

Edit: what I am trying to do is prevent the user pasting a massive amount of characters (~3 million) because it crashes some browsers. So I want to cancel the paste before their browser locks up. I am making a document editor where users are likely to try this. But they can type as much as they want.

Answer 1

you can do this on jQuery like this:

$(document).ready(function(){
function limits(obj, limit){

    var text = $(obj).val(); 
    var length = text.length;
    if(length > limit){
       $(obj).val(text.substr(0,limit));
     } else { // alert the user of the remaining char. I do alert here, but you can do any other thing you like
      alert(limit -length+ " characters remaining!");
     }
 }


$('textarea').keyup(function(){

    limits($(this), 20);
})

  })

view a demo here.

Answer 2

$("textarea").blur(function(event) {
    var maxLength = 3000000;
    var length = this.value.length;
    if (length > maxLength) {
        //reassign substring of max length to text area value
        this.value = this.value.substring(0, maxLength);
        alert(maxLength + ' characters allowed, excess characters trimmed');
    }
});

This jquery attaches the anonymous function to textareas, this will trim the text and alert the user, you can also attach it to the keypress event.

See: http://viralpatel.net/blogs/2008/12/set-maxlength-of-textarea-input-using-jquery-javascript.html for further details on that.