keypress, keyup or keydown only work on the first ring in JQM

Question

in my project have a jQuery Mobile textarea called "topic" on one page

I have this script I am using to count the characters entered in the textarea, but this script just gives me a result on the first keystroke. the other does not.

$(document).delegate("#topicDialog", "pageinit", function() {
$("#topic").keyup(function(e) {
        var tam = $(this).length;

        if (tam <= 61700){
            $("#maxCarac").html(tam +" typed characters. The maximum allowed is 61700");
        } else {
            alert("You have reached the maximum text size.\nPlease break your text into more than one topic.");
            $("#topic").val($("#topic").substring(61700));
        }
    });
});

example in action

What can be happening?

Answer 1

this line needs to be changed

var tam = $(this).val().length;

See Demo

Answer 2

you need to use val().length

check the update fiddle here

$("#topic").keyup(function(e) {
        var tam = parseInt($(this).val().length);

        if (tam <= 61700){
            $("#maxCarac").html(tam +" typed characters. The maximum allowed is 61700");
        } else {
            alert("You have reached the maximum text size.\nPlease break your text into more than one topic.");
            $("#topic").val($("#topic").substring(61700));
        }
    });

http://jsfiddle.net/manishkumarshr/zdEzk/1/

Answer 3

You are retrieving incorrectly the length of the user input. Use this:

var tam = $(this).val().length;

Here a working demo.