JavaScript - Alert Message Before Enter Page

function addOption()
        {   
            var newItem = prompt("Enter New Item");  
            
            if (!newItem == "")
            {
                var answer = confirm ("Are you sure you want to add? ") 
                if (answer)//if answer is true
                {
                    var lstBx = document.getElementById("lstBxEmail");
                      
                    // Now we need to create a new 'option' tag to add to MyListbox 
                    var newOption = document.createElement("option"); 

                    newOption.value = newItem; // The value that this option will have 
                    newOption.innerHTML = newItem; // The displayed text inside of the <option> tags
                       
                    // Finally, add the new option to the listbox 
                    lstBx.appendChild(newOption);             
                    //sort items in listbox in alpha order
                    arrTexts = new Array();

                    for(i=0; i<lstBx.length; i++) 
                    {
                        arrTexts[i] = lstBx.options[i].text;
                    }
                       
                    arrTexts.sort();
                    for(i=0; i<lstBx.length; i++)
                    {
                        lstBx.options[i].text = arrTexts[i];
                        lstBx.options[i].value = arrTexts[i];
                    }                     
                }
                                
                else
                {    
                    if(newItem)
                    {
                        alert("Key something to textbox please.");
                    }
                    
                    else
                        alert("Cancel choice.");
                }                    
            }
        }

                                <center><input id="Submit18" type="submit" value="Add Address" onclick="addOption()"/>

                                
                            <div>Address:</div>
                                <center>
                                <select id="lstBxEmail" name="listBoxEmail" multiple="multiple" style="width: 580px;">
                                      <option>Java</option>
                                      <option>PHP</option>
                                      <option>Perl</option>
                                      <option>Javascript</option>
                                      <option>C#</option>
                                      <option>Powershell</option>                                      
                                    </select>                              
                                </center>

<form action="mailto:hummdedum@felloff.com" method="post" name="form" onSubmit="return isFormValid();">

* First Name: <input type="text"  name="FName" id="FName" onblur="checkFName();"/><label id="labelFName"></label><br />
* Last Name: <input type="text" name="LName" id="LName"onblur="checkLName();"/><label id="labelLName"></label><br />



* Password: <input type="password" id="pw" name="Password" onblur="checkpw();" id="pw"/><label id="labelpw"></label><br />
*Re-type Password: <input type="password" name="2Password" id="pw2" onblur="checkpw2();" /><label id="labelpw2"></label><br />


I am a: <br />
<input type="radio" name="status" value="fresh" /> Freshman<br />
<input type="radio" name="status" value="soph" /> Sophomore<br />
<input type="radio" name="status" value="jr" /> Junior<br />
<input type="radio" name="status" value="sr" /> Senior<br />



I am taking classes in the: <br />
<input type="checkbox" name="semester" value="fall" /> fall time<br />
<input type="checkbox" name="semester" value="spring" /> Spring time <br />



My favorite element is:
	<select name="element" id="element">
                <option value="">select one</option>
		<option value="fire">Fire</option>
		<option value="earth">Earth</option>
		<option value="water">Water</option>
		<option value="air">Air</option>
	</select><br />



*Birthday: <input type="text" id="BDay" name="Birthday" onblur="checkBDay();"/><label id="labelBDay"></label><br />



*E-Mail: <input type="text" id="email" name="Email" onblur="checkEmail();"/><label id="labelEmail"></label><br />


	<input type="submit" value="Submit" />
	<input type="reset" value="Clear" />

</form>

function isFormValid() 
{var userF = document.getElementById('FName').value;
	var userL = document.getElementById('LName').value;
	var userPW = document.getElementById('pw').value;
	var userPW2 = document.getElementById('pw2').value;
	var userBDay = document.getElementById('BDay').value;
	var userEmail = document.getElementById('email').value;
	var NameFormat = /^[A-Za-z]{2,12}$/;
	var PWFormat = /^[A-Za-z0-9{6,12}$]/;
	
	if (!NameFormat.test(userF))
		{
		alert("First Name is required and should only have letters. 2-12 letters max");
		return false;
		}
	if (!NameFormat.test(userL))
		{
		alert("Last Name is required and should only have letters. 2-12 letters max");
		return false;  
		}
	if (!PWFormat.test(userPW))
		{
		alert("Password is required and should only have letters and numbers. 6-12 letters max");
		return false; 
		}
	if (userPW != userPW2)
		{
		alert("Passwords do not match.");
		return false;
		}
	
}
                       
function checkFName()
{
	var userF = document.getElementById('FName').value;
	var elementF = document.getElementById('labelFName');
	var NameFormat = /^[A-Za-z]{2,12}$/;
	if (!NameFormat.test(userF))
		{
		elementF.innerHTML = "First Name is required and should only have letters. 2-12 letters max";
		elementF.style.color = "red";
		}
	else
		{
		elementF.innerHTML = "";
		elementF.style.color = "green"; 
		}
}

function checkLName()
{
	var userL = document.getElementById('LName').value;
	var elementL = document.getElementById('labelLName');
	var NameFormat = /^[A-Za-z]{2,12}$/;
	if (!NameFormat.test(userL))
		{
		elementL.innerHTML = "Last Name is required and should only have letters. 2-12 letters max";
		elementL.style.color = "red";
		}
	else
		{
		elementL.innerHTML = "";
		elementL.style.color = "green"; 
		}
}
function checkpw()
{
	var userPW = document.getElementById('pw').value;
	var elementPW = document.getElementById('labelpw');
	var PWFormat = /^[A-z0-9]{6,12}$/;
	if (!PWFormat.test(userPW))
		{
		elementPW.innerHTML = "Password is required and should only have letters and numbers. 6-12 letters max";
		elementPW.style.color = "red";
		}
	else
		{
		elementPW.innerHTML = "Valid Password";
		elementPW.style.color = "green"; 
		}
}
function checkpw2()
{
	var userPW2 = document.getElementById('pw2').value;
	var userPW = document.getElementById('pw').value;
	var elementPW2 = document.getElementById('labelpw2');
	if (userPW != userPW2)
		{
		elementPW2.innerHTML = "Passwords do not match.";
		elementPW2.style.color = "red";
		}
	else
		{
		elementPW2.innerHTML = "Passwords Match";
		elementPW2.style.color = "green"; 
		}
}

        <fieldset> 
        <select name="filter" alter-data="dropFilter"> 
            <option>Germany</option> 
            <option>Ukraine</option> 
            <option>Estonia</option> 
        </select>    
        <input type="text" alter-data="searchFilter" /> 
    </fieldset>

<script> 
(function($){ 
 
var listview = $('#listview'); 
 
var lists = (function(){ 
    var criteria = { 
        dropFilter: { 
            insert: function(value){ 
                if(value) 
                    return handleFilter("filter", value);   
            }, 
            msg: "Filtering..." 
        }, 
        searchFilter: { 
            insert: function(value){ 
                if(value) 
                    return handleFilter("search", value); 
            }, 
            msg: "Searching..." 
        } 
 
    } 
    var handleFilter = function(key,value){ 
            return {key: value}; 
    } 
    return {   
         create: function(component){ 
            var component = component.href.substring(component.href.lastIndexOf('#') + 1);  
            return component; 
        }, 
         setDefaults: function(component){ 
            var parameter = {}; 
            switch(component){ 
                case "sites": 
                    parameter = { 
                        'order': 'site_num', 
                        'per_page': '20', 
                        'url': 'sites' 
                    } 
            } 
            return parameter; 
        }, 
        getCriteria: function(criterion){ 
            return criteria[criterion];      
 
        }, 
        addCriteria: function(criterion, method){ 
            criteria[criterion] = method;   
        } 
    } 
})();  
 
var Form = function(form){ 
    var fields = []; 
    $(form[0].elements).each(function(){   
        var field = $(this);   
        if(typeof field.attr('alter-data') !== 'undefined') fields.push(new Field(field));   
    })   
} 
 
Form.prototype = { 
    initiate: function(){ 
        for(field in this.fields){ 
            this.fields[field].calculate();  
        } 
    }, 
     isCalculable: function(){   
        for(field in this.fields){   
                if(!this.fields[field].alterData){   
                return false;  
            } 
        }  
        return true;    
    }  
} 
 
var Field = function(field){   
    this.field = field;  
    this.alterData = false;  
    this.attach("change");   
    this.attach("keyup");   
} 
 
Field.prototype = {   
    attach: function(event){ 
        var obj = this;   
        if(event == "change"){ 
            obj.field.bind("change", function(){  
                return obj.calculate(); 
            }) 
        } 
        if(event == "keyup"){ 
            obj.field.bind("keyup", function(e){   
                return obj.calculate(); 
            }) 
        } 
    }, 
    calculate: function(){ 
        var obj = this,   
            field = obj.field,   
            msgClass = "msgClass", 
            msgList = $(document.createElement("ul")).addClass("msgClass"),   
            types = field.attr("alter-data").split(" "),   
            container = field.parent(),  
            messages = []; 
 
        field.next(".msgClass").remove();  
        for(var type in types){   
            var criterion = lists.getCriteria(types[type]);   
            if(field.val()){  
                var result = criterion.insert(field.val());  
 
                container.addClass("waitingMsg");   
                messages.push(criterion.msg);   
 
                obj.alterData = true;   
 
                alert(result); 
                initializeTable(result);   
 
            } 
            else {    
                return false;   
                obj.alterData = false;   
            } 
        } 
        if(messages.length){ 
            for(msg in messages){ 
                msgList.append("<li>" + messages[msg] + "</li");   
            } 
        } 
        else{ 
            msgList.remove();   
        } 
    } 
} 
 
$('#dashboard a').click(function(){ 
    var currentComponent = lists.create(this); 
    var custom = lists.setDefaults(currentComponent); 
    initializeTable(custom); 
}); 
 
var initializeTable = function(custom){ 
    var defaults = {}; 
    var custom = custom || {}; 
 
    var query_string = $.extend(defaults, custom); 
 
    var params = []; 
    $.each(query_string, function(key,value){ 
        params += key + ': ' + value;  
    }) 
    var url = custom['url']; 
 
    $.ajax({ 
        type: 'GET', 
        url: '/' + url, 
        data: params, 
        dataType: 'html', 
        error: function(){}, 
        beforeSend: function(){}, 
        complete: function() {}, 
        success: function(response) {  
            listview.html(response); 
        } 
    }) 
} 
 
$.extend($.fn, {   
    calculation: function(){ 
 
        var formReady = new Form($(this)); 
 
        if(formReady.isCalculable) { 
            formReady.initiate();    
        } 
    } 
 
}) 
 
 
    var form = $('fieldset'); 
    form.calculation(); 
})(jQuery)