textbox length according to text

i have code that dynamically addtextbox but when i add onkeyup function, it work in Chrome and Firefox but it doesn't work in IE.. code that does not work is after the text with red colour. TQ so much.

 

$(document).ready(function () {

var counter = 2;

$("#btnAdd").click(function () {

if (counter > 4) {

return false;
}

var newTextBoxDiv = $(document.createElement('div'))
.attr("id", 'TextBoxDiv' + counter);


newTextBoxDiv.after().html(''" onkeyup="Expand(this);"' + '" id="textbox' + counter + '" value="">');

newTextBoxDiv.appendTo("#LinkTab");

$('#textbox' + counter).focus();
counter++;
}); 

 

 

function Expand(obj) {