get value of hidden type field

1<input type="hidden" id="foo" name="zyx" value="bar" />
2
3alert($('input#foo').val());
4alert($('input[name=zyx]').val());
5alert($('input[type=hidden]').val());
6alert($(':hidden#foo').val());
7alert($('input:hidden[name=zyx]').val());

1// HTML : 
2<input type=hidden id="abcId" name="abcName" value="Wall Street! Money Never Sleep"/>
3  
4  // JAVASCRIPT :
5   alert(document.getElementById('abcId').value);
6   alert(document.formName.elements['abcName'].value);