貓頭鷹的家

convert your variables into jQuery collections and HTML DOC nodes
     var headingFromD = document.getElementById("cuteness"); // DOM node
    headingFromD.innerHTML = "Setting .innerHTML";
     var $heading = $("#cuteness");        // jQuery collection
    $heading.html("Using jQuery again!");
    
    var headingD = $heading[0];   //convert jQuery collection to DOM node
    var $headingJ = $(headingD);  //convert DOM node to jQuery collection