JavaScript - Checkbox Array - Ability To Check All

<input  name="pass" type="password" class="textfield" />
<input  type="checkbox" class="check"> Click here to show/hide password

<input  name="pass" class="textfield" />

<input  name="pass" type="password" class="textfield" />

<div id="title">
        <p class="white">1</p>
    </div>
    <div id="question">
    	<p>Please indicate your area(s) of interest below:<br />
        <input type=checkbox value="1" />  Option 1<br />
        <input type=checkbox value="2" />  Option 2<br />
        <input type=checkbox value="3" />  Option 3<br />
        <input type=checkbox value="4" />  Option 4</p>
    </div>

<form id="simplesearch" name="simplesearch">
<input type="checkbox"   onclick='showhidefield(this.value)' name="meta_data_array_search_criteria[custom_profile_type][]" value="5"  class="input-checkboxes" />
<input type="checkbox"   onclick='showhidefield(this.value)' name="meta_data_array_search_criteria[custom_profile_type][]" value="4"  class="input-checkboxes" />
</form>

function showhidefield(id)
{
   if(document.simplesearch.meta_data_array_search_criteria[custom_profile_type][''].checked) {
      document.getElementById("profile_fields_wrapper_" + id).style.visibility = "visible";
   }
   else
   {
      document.getElementById("profile_fields_wrapper_" + id).style.visibility = "hidden";
   }
}

			while ($row = mysql_fetch_array($data, MYSQL_ASSOC)) 
			{
				if(is_null($row['Team_Number']))
				{
					$str1 = sprintf('<input type="checkbox" name=\'People\' value="%s">',$row['Member_ID']);
				}
				else if($row['Team_Number'] == $_REQUEST['T'])
				{
					str1 = sprintf('<input type="checkbox" name=\'People\' value="%s" checked>',$row['Member_ID']);
				}
				else
				{
					$str1 = sprintf('<input type="checkbox" name=\'People\' value="%s">',$row['Member_ID']);
				}
				
				$str = sprintf('%s,%s (%s)',$row['First'],$row['Last'],$row['Nick_Name']);
				echo('<tr><td width ="10%" align="center">');
				echo($str1);
				echo('</td><td width="90%" align="Left">');
				echo($str);	 
				echo('</td >');
				echo('</tr></td>');
			}

function TeamSetup()
{
	var required = document.form1.BowlersPerTeam.value;
	var total = document.form1.People.length;
	var Tm = document.form1.TeamName.value;
	var cnt = 0;
	var peopleIDs = "";
	
	var test = document.getElementsByName('People');
	
	if(isArray(document.form1.People))
	{
		for(var i=0; i < total; i++)
		{
			if(document.form1.People[i].checked)
			{
				if(peopleIDs.length > 0)
				{
					peopleIDs = peopleIDs +",";
				}
				peopleIDs = peopleIDs + document.form1.People[i].value.toString();
				cnt++;
			}
		}
	}
	else
	{
		if(document.form1.People.checked)
		{
			cnt=1;
			peopleIDs = peopleIDs + document.form1.People.value.toString();
			
		}
	}
	
	  if(Tm.length > 0)
	  {
		  if(cnt == required || cnt > 0)
		  {
			  //Hand off to next step for completeing Processing.
			  var myForm = document.createElement("form");
			  myForm.action=window.location;
			  myForm.method="Post";
			  myForm.appendChild(createformInput("Process","PP"));
			  myForm.appendChild(createformInput("people",peopleIDs));
			  myForm.appendChild(createformInput("Team",GetQueryString("T")));
			  myForm.appendChild(createformInput("League",GetQueryString("L")));
			  myForm.appendChild(createformInput("TeamName",Tm));
			  document.body.appendChild(myForm);
			  myForm.submit();
		  }
		  else
		  {
			  alert('You need to Select at least 1 player');
		  }
	  }
	  else
	  {
		  alert('You need to enter the team name!');
	  }
}

<script type="text/javascript">

function chkChecks(){
isChecked=false
alert(document.forms["form1"]["checked[]"].length);
for(var i=0;i<document.forms["form1"]["checked[]"].length;i++){
if(document.forms["form1"]["checked[]"][i].checked){
isChecked=true
}
}

if(isChecked){
document.forms["form1"].submit()
}
else{
alert('Please select a checkbox')
}

}

</script>

<form name="form1" action="test.php">
<input type="checkbox" name="checked[]" value="1">
<input type="checkbox" name="checked[]" value="2">
<input type="checkbox" name="checked[]" value="3">
<input class="button_140" type="button" value="Check" onclick="chkChecks()">
</form>

function checkAll()
{
if(document.resultForm.master.checked== true)
{
for(var i=0; i < document.resultForm.choices.length; i++)
{
document.resultForm.choices[i].checked=true;
}
}
else
{
for(var i=0; i < document.resultForm.choices.length; i++)
{
document.resultForm.choices[i].checked=false;
}
}
}

<input type="checkbox" name="master">

<input type="checkbox" name="choices" value="choice 1">
<input type="checkbox" name="choices" value="choice 2">
<input type="checkbox" name="choices" value="choice 3">
<input type="checkbox" name="choices" value="choice 4">

<input type="checkbox" name="master">

<input type="checkbox" name="choices[]" value="choice 1">
<input type="checkbox" name="choices[]" value="choice 2">
<input type="checkbox" name="choices[]" value="choice 3">
<input type="checkbox" name="choices[]" value="choice 4">

<html> 
<head> 
            <script> 
            function Check(chk) 
            { 
            for (i=0; i < chk.length; i++) chk[i].checked=document.ListActionForm.Check_ctr.checked ; 
            } 
        function desubmit() 
            { 
            if(get_args()==false) {alert("nothing_selected");return false;} 
            if(labelling(true)) return false; 
            } 
            function labelling(s) {return true;} 
        function get_args() 
            { 
            s=chkboxa2str(document.ListActionForm['listaction[]']); 
            if(s)alert(s); 
            if(s.length<8)return false; 
            else return s; 
            } 
            function chkboxa2str(chkbox_a) {  
            var list = "";  
                for(var i = 0; i < chkbox_a.length; i++){ if(chkbox_a[i].checked) { list += chkbox_a[i].value + " "; } } 
            return list;  
            } 
            </script> 
</head> 
<body> 
<form action="?h=1296078874" method="post" name="ListActionForm" onsubmit="return desubmit()"> 
<input type='checkbox' name='listaction[]' value='2010102909103530'> Testbox 1<br> 
<input type='checkbox' name='listaction[]' value='2010102909103532'> Testbox 2<br> 
<input type="Submit" name="Submit" value="Versturen" > 
</form> 
</body> 
</html>

<?php
//php which sets users array to the results of the sql
$selectquery = "SELECT Username FROM User";
$selectresult = mysql_query($selectquery);
while ($row = mysql_fetch_array($selectresult)){
	$users[] = $row['Username'];

}
?>



<script language="javascript" type="text/javascript">
function verifyUsername(array_var){

	var user = document.getElementById("username").value;
	
	for(var i=0; i<array_var.length; i++){
		if(array_var[i] == user){
			document.getElementById("usernameerror").textContent = "already in array";
		}
	}
}
</script>



//html code for the form
Username: <input type="text" name="username" id="username" onblur="return verifyUsername(<?php $users?>)"/>
        
<span id="usernameerror" class="red"></span>

function additem(id) {
itemName = document.getElementById('name' + id).innerHTML;		itemQuantity = parseInt(document.getElementById('quantity' + id).value);
itemPrice = parseFloat(document.getElementById('price' + id).innerHTML);
if(numitems == 0){	
items[++numitems] = new Item(itemName,itemPrice,itemQuantity);
displaycart();
}
else{
checkarray(id, itemName, itemQuantity, itemPrice);
}
		
}

function checkarray(id, itemName, itemQuantity, itemPrice){

for(i=1;i<=numitems;i++) {
if(items[i].name == itemName){
items[i].quantity += parseInt(document.getElementById('quantity' + id).value);
displaycart();
return true;
}
		
items[++numitems] = new Item(itemName,itemPrice,itemQuantity);
}	
 
}

<input name="q" cid="q" size="25" maxlength="50" value"off road tires">
<input type="checkbox" name="q" id="q" value="cooper|hankook" />
<input type="checkbox" name="q" id="q" value="Mickey Thompson|Bfgoodrich|GBC" />
<input type="checkbox" name="q" id="q" value="Hoosier|Nitto" />

results.html?q=off road tires AND inurl:cooper|hankook|Mickey Thompson|Bfgoodrich|GBC