$(document).ready(function()
{
$("#contentbox").keyup(function()
{
var box=$(this).val();
var main = box.length *100;
var value= (main / 145);
var count= 145 - box.length;

if(box.length <= 145)
{
$('#count').html(count);
$('#bar').animate(
{
"width": value+'%',
}, 1);
}
else
{
alert(' Full ');
}
return false;
});

});

#bar
{
background-color:#5fbbde;
width:0px;
height:16px;
}
#barbox
{
float:right; 
height:16px; 
background-color:#FFFFFF; 
width:100px; 
border:solid 2px #000; 
margin-right:3px;
-webkit-border-radius:5px;-moz-border-radius:5px;
}
#count
{
float:right; margin-right:8px; 
font-family:'Georgia', Times New Roman, Times, serif; 
font-size:16px; 
font-weight:bold; 
color:#666666
}
#contentbox
{
width:450px; height:50px;
border:solid 2px #006699;
font-family:Arial, Helvetica, sans-serif;
font-size:14px;
}

<div>
<div id="count">145</div>
<div id="barbox"><div id="bar"></div></div>
</div>
<textarea id="contentbox"></textarea>

var maxLen=145;
var str=$("#contentbox").val();
$("#contentbox").val(str.split(maxLen+1,str.length-1)[0]);