Limiting number of lines and letters in single line in textarea

Question

Problem:
I am trying to limit number of lines AND letters in each line in a textbox.

What i got so far:
So far i managed to limit lines count using this:

var text = $(this).val();
var lines = text.split("\n");

if(e.keyCode == 13 && lines.length >= $(this).attr('rows')) { 
        return false;
    }

This won't allow user to push return key (keyCode 13) if the limit of lines is reached.

The problem:
Now i am trying to limit number of letters in a single line too, because if i reach end of my textarea (with return key) i still can hold a letter/write tons of text, and it will jump to another line when it reaches end of line. That way this limitation can be "cheated" and i am looking for a solution for that.

My ideas, not solving the problem:

else{
    for(var i = 0; i < lines.length && e.keyCode != 13; i++) {
         if(lines[i].length >= $(this).attr('cols')) {
             return false; // prevent characters from appearing
         }
     }
}

I tried this to limit number of letters. That works, but it got flaws. If i reach max letters in one line (ANY), i CANT TYPE IN ANY LINE anymore.

I have no idea how to check only line i am typing in RIGHT NOW.

Answer 1

Tested in chrome : http://jsfiddle.net/3e3EH/1/

$(document).ready(function(){
    var textArea = $('#foo');
    var maxRows = textArea.attr('rows');
    var maxChars = textArea.attr('cols');
    textArea.keypress(function(e){
        var text = textArea.val();
        var lines = text.split('\n');
        if (e.keyCode == 13){
            return lines.length < maxRows;
        }
        else{
            var caret = textArea.get(0).selectionStart;
            console.log(caret);

            var line = 0;
            var charCount = 0;
            $.each(lines, function(i,e){
                charCount += e.length;
                if (caret <= charCount){
                    line = i;
                    return false;
                }
                //\n count for 1 char;
                charCount += 1;
            });

            var theLine = lines[line];
            return theLine.length < maxChars;
        }
    });

});​

Edit

As jbabey pointed out, ctrl+v or right-click -> paste can be an issue. right click can easily be prevented. for ctrl+v, you probable can detect it too... Just disabling javascript will obviously break the thing, too. Anyways, as any client-side validation, you have to double check on server-side.

Answer 2

Here's what I came up with. Fairly clean and seems to work for all the tests I can give it.

JavaScript:

$(function () {
    $('textarea').on('keypress', function (event) {
        var text = $('textarea').val();
        var lines = text.split("\n");
        var currentLine = this.value.substr(0, this.selectionStart).split("\n").length;
        console.log(lines);
        console.log(currentLine);
        console.log(lines[currentLine - 1]);
        if (event.keyCode == 13) {
            if (lines.length >= $(this).attr('rows')) return false;
        } else {
            if (lines[currentLine - 1].length >= $(this).attr('cols')) {
                return false; // prevent characters from appearing
            }
        }
    });
});

HTML:

<textarea rows="10" cols="15"></textarea>

DEMO