JQuery - Positve/Negative Number(3 digits only) Max-Min-Range

<%@ Page Title="Test Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"

    CodeBehind="TestPage.aspx.cs" Inherits="DeveloperTest01.About" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">

    <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script>

    <script type="text/javascript">    

        $(function () {      

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

                var num1 = $('input:text[name=text0]').val();

                var num2 = $('input:text[name=text1]').val();

                var num3 = $('input:text[name=text2]').val();

                var num4 = $('input:text[name=text3]').val();

                var num5 = $('input:text[name=text4]').val();

                var num6 = $('input:text[name=text5]').val();

                var num7 = $('input:text[name=text6]').val();

                var num8 = $('input:text[name=text7]').val();

                var num9 = $('input:text[name=text8]').val();

                var points = [num1, num2, num3, num4, num5, num6, num7, num8, num9];

                points.sort(function (a, b) { return a - b });

                for (var i = 0; i < points.length; i++) {

                    $("input:text[name=text" + i + "]").val(points[i]);

                }

            });

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

                var num1 = $('input:text[name=text0]').val();

                var num2 = $('input:text[name=text1]').val();

                var num3 = $('input:text[name=text2]').val();

                var num4 = $('input:text[name=text3]').val();

                var num5 = $('input:text[name=text4]').val();

                var num6 = $('input:text[name=text5]').val();

                var num7 = $('input:text[name=text6]').val();

                var num8 = $('input:text[name=text7]').val();

                var num9 = $('input:text[name=text8]').val();

                var _array = [num1, num2, num3, num4, num5, num6, num7, num8, num9];

               var max =  Math.max.apply(Math, _array); // 3

               var min = Math.min.apply(Math, _array); // 1

               document.getElementById("spnMax").innerHTML = max;

               document.getElementById("spnMMin").innerHTML = min;

               document.getElementById("spnRange").innerHTML = max - min;

               var sum = 0;

               var avg = 0;

               var num = 9;

               for (var i = 0; i < _array.length; i++) {

                   sum += Number(_array[i]);

               }            

               if (num > 0) { avg = Number(sum / num); }

               document.getElementById("spnMean").innerHTML = avg.toFixed(2);

            });        

         

            var t = false

            $('input').focus(function () {

                var $this = $(this)

                t = setInterval(

                function () {

           if (($this.val() < -999 || $this.val() > 999) && $this.val().length != 0) {

                        if ($this.val() < 1) {

                            $this.val("")

                        }

                        if ($this.val() > 999) {

                            $this.val("")

                        }

                        $('p').fadeIn(1000, function () {

                            $(this).fadeOut(500)

                        })

                    }

                }, 50)

            })

            $('input').blur(function () {

                if (t != false) {

                    window.clearInterval(t)

                    t = false;

                }

            })

            $('input').keypress(function (e) {

                //if the letter is not digit then display error and don't type anything

                if (e.which != 8 && e.which != 45 && (e.which < 48 || e.which > 57)) {

                    //display error message

                    $("#errmsg").html("Digits Only").show().fadeOut("slow");

                    return false;

                }

            });

        });

    </script>

</asp:Content>

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">

     <p style="display:none">Accepting Only values 3 digits</p>

    <table>

        <tr>

            <td>

                <input type="text" name="text0" id="text0" style="width: 50px"  value="" />

            </td>

            <td>

                <input type="text" name="text1"  id="text1" style="width: 50px" value="" />

            </td>

            <td>

                <input type="text" name="text2" id="text2" style="width: 50px" value="" />

            </td>

            <td>

                <input type="text" name="text3" id="text3" style="width: 50px" value="" />

            </td>

            <td>

                <input type="text" name="text4" id="text4" style="width: 50px" value="" />

            </td>

            <td>

                <input type="text" name="text5" id="text5" style="width: 50px" value="" />

            </td>

            <td>

                <input type="text" name="text6" id="text6" style="width: 50px" value="" />

            </td>

            <td>

                <input type="text" name="text7" id="text7" style="width: 50px" value="" />

            </td>

            <td>

                <input type="text" name="text8" id="text8" style="width: 50px" value="" />

            </td>

        </tr>

    </table>

    <input id="btnsort" name="btnsort" type="button" value="Sort" />

    <input id="btnPopulate" name="btnPopulate" type="button" value="Populate" />

    <br />  <br />

    Max : <span id="spnMax"></span><br />

    Min :  <span id="spnMMin"></span><br />

    Mean : <span id="spnMean"></span><br />

    Range : <span id="spnRange"></span><br />

</asp:Content>