Mutual reference of variables in JavaScript_javascript skills

The test is as follows:

Array type test Object type test Instantiated function test Function parameter passing test by address
var a=b=[1,2]; a.push(3); alert(a.length ' : ' b.length);

About the impact on node object operations:

Since the function is passed by value, when inserting a node, the node itself is referenced, not one of its clones, so the node is transferred

For example:

<meta http-equiv="Content-Type" content="text/html; charset=gb2312"> <title> </title>Untitled Document<style type="text/css"> .c2{ border:1px solid #ccc; width:100px; height:100px;} .c1{ border:2px solid #000; width:50px; height:60px;} </style> <div class="c1" id="div1"> </div>div1<div class="c2" id="div2"> </div>div2<input type="button" value="append div1 to div2" id="button">