Get check box number / value

======= What did the user check =========
<input type="checkbox" name="userListCheck" value=“1" onClick="buttonUpdate()">
<input type="checkbox" name="userListCheck" value=“2" onClick="buttonUpdate()">
………..
………..
--- Javascript ----
function buttonUpdate() {
var checkboxLength = document.getElementsByName("userListCheck").length;

for (var i = 0; i < checkboxLength ; i++ ) {
if (document.getElementsByName("userListCheck")[i].checked == true) {
//Do something when the check box is checked over one
//such as > UIManager.getInstance().getControl("RemoveButton").setEnabled(true);
break;
} else {
//Do something when the check box is not checked anything
//UIManager.getInstance().getControl("RemoveButton").setEnabled(false);
}
}
}

======= Get check value =========
---- HTML Part ----
<input type="checkbox" name="userListCheck" value=“1" onClick="buttonUpdate()">
<td width="270" class="Base1" id="userListName1" value=“1'">
<p>name</p></td>
<input type="checkbox" name="userListCheck" value=“2" onClick="buttonUpdate()">
<td width="270" class="Base1" id="userListName2" value=“2'">
<p>name</p></td>

………..

---- Javascript ----
function buttonUpdate() {
var checkboxLength = document.getElementsByName("userListCheck").length;

for (var i = 0; i < checkboxLength ; i++ ) {
if (document.getElementsByName("userListCheck")[i].checked != true) {
selectedValue = document.getElementsByName("userListCheck")[i].value;
selectedName = document.getElementById("userListName"+selectedValue).value;}
}
}
}