Javascript validation on multiline texbox for character count-2

Javascript validation on multiline texbox for character count-2

<script type="text/javascript">
                function checkTextAreaMaxLength(textBox, e, length) {

                    var mLen = textBox["MaxLength"];
                    if (null == mLen)
                        mLen = length;

                    var maxLength = parseInt(mLen);
                    if (!checkSpecialKeys(e)) {
                        if (textBox.value.length > maxLength - 1) {
                            textBox.value = textBox.value.substring(0, maxLength);

                            if (window.event)//IE
                                e.returnValue = false;
                            else//Firefox
                                e.preventDefault();
                        }
                    }
                }

function checkSpecialKeys(e)

{
   if (e.keyCode != 8 && e.keyCode != 46 && e.keyCode != 37 && e.keyCode != 38 && e.keyCode != 39 && e.keyCode != 40)
                        return false;
                    else
                        return true;
}    
 
            </script>

---------------------
 
 <asp:TextBox Rows="5" Columns="20" Width="180px" ID="txtDescription" MaxLength="150"
    onkeyDown="checkTextAreaMaxLength(this,event,'150');"
   TextMode="multiLine" runat="server"> </asp:TextBox>
---------------------

Posted in: JAVASCRIPT,VALIDATIONS