Issue with closest(".coral-Select"); in aem 6.5

when am trying to get an value from drop down in selection field using closest(".coral-Select") getting an undefined value.
is there any change in aem 6.5? but it works fine in aem 6.3.
EX: var a = $("[name='./componentMode']").closest(".coral-Select");

if iam trying to print $("[name='./componentMode']") ,value is getting populated in console,when iam trying with $("[name='./componentMode']").closest(".coral-Select"); getting undefined in console.
can you suggest any solution.