Find status of Checkbox

Find status of Checkbox

Hi,
i have this code:
fieldset data-role="controlgroup" data-iconpos="right" id="control">
        <legend>PIck a  language:</legend>
          <label for="gr">Greek</label>
          <input type="checkbox" name="favcolor_gr" id="gr" value="greek" onchange="myFunction()">
          <label for="en">English</label>
          <input type="checkbox" name="favcolor_en" id="en" value="engl">
          <label for="fr">French</label>
          <input type="checkbox" name="favcolor_fr" id="fr" value="french">
          <label for="ger">German</label>
          <input type="checkbox" name="favcolor" id="ger" value="german">
          <label for="rus">Russian</label>
          <input type="checkbox" name="favcolor" id="rus" value="russian">                      
      </fieldset>

When i am running this function  i'm not getting anything as output:
<script>
function myFunction()
{
 if($("#gr").is(:checked))
     alert("Test");
}
</script>


Any thoughts?