How to get the number of lines in a textarea?

The problem with using "\n" or "\r" is it only counts the number of returns, if you have a line that is long it could wrap and then it wouldn't be counted as a new line. This is an alternative way to get the number of lines - so it may not be the best way.

Edit (thanks alex):

Script

$(document).ready(function(){
 var lht = parseInt($('textarea').css('lineHeight'),10);
 var lines = $('textarea').attr('scrollHeight') / lht;
 console.log(lines);
})

Update: There is a much more thorough answer here: https://stackoverflow.com/a/1761203/145346

If you are just wanting to test hard line returns, this will work cross platform:

var text = $("#myTextArea").val();   
var lines = text.split(/\r|\r\n|\n/);
var count = lines.length;
console.log(count); // Outputs 4

I have implemented the lines and lineCount methods as String prototypes:

String.prototype.lines = function() { return this.split(/\r*\n/); }
String.prototype.lineCount = function() { return this.lines().length; }

Apparently the split method will not count a carriage return and/or newline character at the end of the string (or the innerText property of a textarea) in IE9, but it will count it in Chrome 22, yielding different results.

So far I have accomodated for this by subtracting 1 from the line count when the browser is other than Internet Explorer:

String.prototype.lineCount = function() { return this.lines().length - navigator.userAgent.indexOf("MSIE") != -1); }

Hopefully someone has a better RegExp or another workaround.