Checkbox value is always 'on' [duplicate]
Use .is(':checked') instead: Working jsFiddle
var eu_want_team = $('#eu_want_team').is(':checked');
alert(eu_want_team);
or as @Itay said in comments you can use jQuery's .prop() to get the checked property value:
alert($("#eu_want_team").prop("checked"));
<label class="checkbox">
<input id="eu_want_team" name="eu_want_team" type="checkbox" value="somevalue">
</label>
<script>
var ele = document.getElementById("eu_want_team");
if(ele.checked)
alert(ele.value)
</script>