javascript - Ask for multiple id's with the same data attribute -

i'm trying check data attribute in multiple list items.

my html:

<ul id="year">   <li id="2006">2006</li>   <li id="2007">2007</li>   <li id="2008">2008</li>   <li id="2009">2009</li>   <li id="2010">2010</li>   <li id="2011">2011</li>   <li id="2012">2012</li>   <li id="2013">2013</li>   <li id="2014">2014</li> </ul> 

and jquery:

jquery('#year li').click(function() {     var year = jquery(this).attr('id');     if ((jquery(this).data('state') === undefined) || (jquery(this).data('state') == "off"))     {         jquery(this).data('state', 'on');     }     else     {         jquery(this).data('state', 'off');     } }); 

now trying check if there list items "state" == "on" this:

if ((jquery('#year li').data('state') == "on")) 

but not seem working...

edit: tried different snippets gave me: none of them worked made simple loop looks in every list point itself:

    ( var y = 2006, l = 2015; y < l; y++ )     {     if ((jquery('#year #'+y).data('state') == "on"))     {         alert('data found');     } 

another problem didnt had event before code! support!

the jquery('#year li') return array of jquery objects.

you need loop each one

$('#year li').each(function () {     if ((jquery(this).data('state') === "on")){         alert("on state found");     } });