JavaScript - Hiding Variables From Client

function toggleDiv (divid) {
	if (document.getElementById (divid).style.display == 'none') {
		document.getElementById (divid).style.display = 'block';
	} else {
		document.getElementById (divid).style.display = 'none';
	}
}

<a href="javascript:;" class="showmorelink" onmousedown="toggleDiv('checks');">Safeguarding</a>

* { margin:0; padding:0; }
body { background:#111; height:100%; }
	img{ border:none; }
	
	
	
	#supersized { position:absolute; left:0; top:0; overflow:hidden; z-index:-999; height:50%; width:100%; }
		#supersized img{ width:auto; height:auto; position:relative; display:none; outline:none; border:none; }
			#supersized.speed img { -ms-interpolation-mode:nearest-neighbor; image-rendering: -moz-crisp-edges; }	/*Speed*/
			#supersized.quality img { -ms-interpolation-mode:bicubic; image-rendering: optimizeQuality; }			/*Quality*/
		
		#supersized a { z-index:-30; position:fixed; overflow:hidden; top:0; left:0; width:100%; height:50%; background:#111; display:block; }
			#supersized a.prevslide { z-index:-20; }
			#supersized a.activeslide { z-index:-10; }
			#supersized a.image-loading { background:#111 url(../img/progress.gif) no-repeat center center; width:100%; height:50%; }
			#supersized a.prevslide img, #supersized a.activeslide img{ display:inline; }

<td>
<script type="text/javascript">
if ([fieldXX]==1)   
 {
 document.write("<a href='page1.asp?itemid=1234'><img src='images/btn-choose.gif' border='0' alt='choose button'</a>"); 
 } 
else
 {  
    var id = 'hide-buy-btn';
    var item = document.getElementById(id); 
 if (item) {
 item.className=(item.className=='hidden')?'unhidden':'hidden';
 }
 }
</script>

<div id="hide-buy-btn" class="hidden">
x
xother button code
x						
</div>
</td>

// hashslider v0.9 by manuel huegel, copyright 2010
// mgoys.com


$(document).ready(function(){
					   
//get width and height of the wrapper and give it to the UL	
	var wrapperwidth = $('#slider').width() *  $('#slider ul > li').size();
	$('#slider ul').css('width', wrapperwidth);
	var wrapperheight = $('#slider').height();
	$('#slider ul').css('height', wrapperheight);	
						   
						   
//set my li width
	var width = $('#slider').width();
	$('#slider ul li').css('width', width);

//set my counter vars
	var counter = $('#slider ul > li').size();
	var decount = 1;
	var autocount = 1;
	
//create my number navigation
	var createNum = 1;
	$('#numbers li:first-child').html(createNum).addClass('activenum').attr('id', 'id1');
	while ( createNum != counter) {
	$('#numbers li:last-child').after('<li>  </li>');
	createNum++;
	$('#numbers li:last-child').html(createNum);
	$('#numbers li:last-child').attr('id', 'id' + createNum);
	}
	
//get my number-width (number navigation should always be centered)
	var numwidth = $('#numbers li:first-child').width() * $('#numbers li').size();
	$('#numbers').css('width', numwidth);


	
//slide the button to the next item
function goNext() {
	if ( decount != counter) {
	$('#slider ul').animate({ left: '-=' + $('#slider').width() }, 400, 'swing', function() { });
	$('.activenum').removeClass('activenum').next().addClass('activenum');
	decount++;
	window.location.hash = decount;
	}
}

function goBack() {
	if ( decount != 1) {
	$('#slider ul').animate({ left: '+=' + $('#slider').width() }, 400, 'swing', function() { });
	$('.activenum').removeClass('activenum').prev().addClass('activenum');
	decount--;
	window.location.hash = decount;
	}
}

//make the number clickable
$("#numbers li").click(function() { 
	//$('#info4').html( $(this).html() ); 
	var clickednum = $(this).html() * - $('#slider').width() + $('#slider').width();
	//$('#info4').html( clickednum );
	$('#slider ul').animate({ left: clickednum }, 400, 'swing', function() { });
	$('.activenum').removeClass('activenum');
	$(this).addClass('activenum');
	decount = $(this).html();
	window.location.hash = $(this).html();	
});


//thaths the hash-shizzle
if ( window.location.hash != '') {
//get hash, scroll to position
	var hashnum = window.location.hash.substr(1) * - $('#slider').width() + $('#slider').width();
	$('#slider ul').animate({ left: hashnum }, 0, function() { });
//set counters to position
	decount = window.location.hash.substr(1);
	$('.activenum').removeClass('activenum');
	var hashname = window.location.hash.substr(1);
	$('#id' + hashname).addClass('activenum');
}
	
//get my clickers
$("#right").click(function() { goNext(); });	
$("#left").click(function() { goBack(); });	


//get mousewheel function
$("#slider ul").mousewheel(function(event, delta) { if (delta > 0) { goBack();	event.stopPropagation();event.preventDefault(); } });
$("#slider ul").mousewheel(function(event, delta) { if (delta < 0) { goNext();  event.stopPropagation();event.preventDefault();	} });







});

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
    <script type="text/javascript" src="client_validation.js" /> 
	</script>
<link rel="stylesheet" type="text/css" href="Client validation.css" />
	<title> Client Validation </title>
	
	</head>
 
 <body>
 <form name="contact_form" method="post" action="submit" onsubmit="return validate_form ( );">
 <h3><strong>Client Validation</strong></h3>
 
 
<p>Your Name: <input type="text" name="text1"></p>
<p>Your Last Name: <input type="text" name="text2"></p>
<p>Email:  <input type="text" id="email" name="text3"></p>
<p>Phone: <input type="text" name="text4"></p>
<p>Address: <textarea cols="20" rows="5" name="text5"></textarea></p>
<p>Do you agree to the Terms and Conditions?
<input type="checkbox" name="text6" value="Yes"> Yes

<p><input type="submit" name="send" value="Send Details"></p>
</form>

Your Email: <form id="form_id" method="post" action="action.php" onsubmit="javascript:return validate('form_id','email');">
   <input type="text" id="email" name="email" />
   <input type="submit" value="Submit" />
   

<form method="post" action="data.php" name="form1">
 <p>Enter Number
 <input type="text" name="phoneNo"></p>
 <input type="button" name="btn1" value="submit" onClick="CheckNumber()">



 </body>
 </html>

function validate_form ( )
{
	valid = true;

        if ( document.contact_form.text1.value == "" )
        {
                alert ( "Please fill in the 'Your First Name' box." );
                valid = false;
        }

		if ( document.contact_form.text2.value == "" )
        {
                alert ( "Please fill in the 'Your Last Name' box." );
                valid = false;
        }
				
		if ( document.contact_form.text5.value == "" )
		{
		       alert ( "Please fill in your address." );
			   valid = false;
		}
		
		if ( document.contact_form.text6.checked == false )
        {
                alert ( "Please check the Terms & Conditions box." );
                valid = false;
        }
		
		return valid;
}

function validate(form_id,email) {
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   var address = document.forms[form_id].elements[email].value;
   if(reg.test(address) == false) {
      alert('Invalid Email Address');
      return false;
   }
}

function CheckNumber() {
var PhoneNumber=document.form1.phoneNo.value;
for (var i=0; i<PhoneNumber.length; i++) {
          var c=PhoneNumber.charAt(i);
          if (!(c>0 || c<9)){ 
                    alert("This is not a valid Phone Number");
                     break;
 }   } }