验证不是't工作，现在我的网站也坏了

我在"插入数字，输出答案"方面做得很好。但我需要在网站上进行验证，这样只有某些东西才能起作用。我的网站在进行验证时，完全停止了工作，我不完全理解为什么或发生了什么。

JS小提琴：http://jsfiddle.net/ufs869wu/

HTML:

 <form id="form1" name="form1" method="post" action="">
            <label for="txtAge">Age:</label>
            <input type="text" class="txtInput" id="txtAge" value="0"/><p id="ageRes"></p>
            <br/>
            <label for="txtMass">Mass in Lbs:</label>
            <input type="text" class="txtInput" id="txtMass" value="0"/>
            <br/>
            <label for="txtHinch">Height in Inches:</label>
            <input type="text" class="txtInput" id="txtHinch" value="0"/>
            <br/>
            <input type="button" id="btnCalc" value="Calculate"/>
            <p id="result2">Result</p>
        </form>
        <script src="http://code.jquery.com/jquery-latest.min.js"></script>
        <script src="BMI.js"></script>
</body>

和JS

// JavaScript Document
$(function () {
    //Identify Variables
    var txtMass, txtHinch, result;
    var isValid = $('#form1').validate().form();
    // attach event listener to the toggle button's click event

    $('#btnCalc').click(function () {
        //Set validator
            $.validator.setDefaults({
            errorElement: "span",
            errorClass: "form_error",
            errorPlacement: function(error,element){
                error.insertAfter(element)
                }
            });
            $.extend($.validator.messages,{
            required: "* Required field"
            });
            //Set Validation perameters
            $("#form1").validate({
            rules: {
                txtAge: {
                    required: true,
                    range: [1, 120],
                    digits: true
                },
                txtMass: {
                        require: true,
                        digits: true
                },
                txtHinch: {
                    requre: true,
                    digits: true
                }
            }
            });
        if (isValid) {
            //Set Age range for form accuracy
            if (txtAge < 16 || txtAage > 80){
            //Output
            $('#ageRes').html('Results may not be accurate at your age')
            } else { (txtAge >= 16 || txtAge <= 80)
            $('#ageRes').html('Results should be accurate considering your age')


            //Equation for BMI
            result = ($('#txtMass').val() / ($('#txtHinch').val() * $('#txtHinch').val())) * 703;}
            //If - Else statement from output of BMI equation
            if (result < 16){
            $('#result2').html('Result: '+result.toFixed(1) + ' you are Severely underweight')
            } else if (result <=18 ){
            $('#result2').html('Result: '+result.toFixed(1) + ' you are underweight')
            } else if (result <=24){
            $('#result2').html('Result: '+result.toFixed(1) + ' you are healthy')
            } else if (result <= 30 ){
            $('#result2').html('Result: '+result.toFixed(1) + ' you are seriously overweight')
            } else if (result <=35 ){
            $('#result2').html('Result: '+result.toFixed(1) + ' you are obese')
            } else if (result <=40 ){
            $('#result2').html('Result: '+result.toFixed(1) + ' you are seriously obese')
            }
            }

    });

});

感谢您的帮助！