Functions should return a value

no-function.js

var contentEl = $('foo').hasClass('content') ? target : $(target).closest('.content');

no-return-value.js

var contentEl;

function getContentEl(target) {
  contentEl = $(target).hasClass('content') ? target : $(target).closest('.content');
}

getContentEl('foo');

return-value.js

var contentEl;

function getContentEl(target) {
  return $(target).hasClass('content') ? target : $(target).closest('.content');
}

contentEl = getContentEl('foo');