javascript - Find class name -


how can find class

<div class="sidebar-toggle sidebar-collapse" id="sidebar-collapse">     <i class="ace-icon fa fa-angle-double-right" data-icon2="ace-icon fa fa-angle-double-right" data-icon1="ace-icon fa fa-angle-double-left"></i> </div> 

i want find ace-icon fa fa-angle-double-right have tried this

    var sidebar_collapse = document.getelementbyid("sidebar-collapse");     $(sidebar_collapse).on('click', function () {         var angel_double_right = $(sidebar_collapse).find('.ace-icon fa fa-angle-double-right');         if (angel_double_right) {             alert("yeah has class");             $(ticksign).css('display', 'none');         }     }); 

but not working. alert every time

access child , class name:

document.write(json.stringify(document.getelementbyid("sidebar-collapse").children[0].classname));
<div class="sidebar-toggle sidebar-collapse" id="sidebar-collapse">      <i class="ace-icon fa fa-angle-double-right" data-icon2="ace-icon fa fa-angle-double-right" data-icon1="ace-icon fa fa-angle-double-left"></i>  </div>