<div class="codetitle"> <span><a style="CURSOR: pointer" data="3522" class="copybut" id="copybut3522" onclick="doCopy('code3522')"><u>Copy code</u></a></span> The code is as follows:</div> <div class="codebody" id="code3522"> <br><script type="text/javascript"> <br> var a="1"; <br>var b=false; <br>var c="dd"; <br>var d={ <br>valueOf:function(){return -1} <br>}; <br>alert(a);//Output 1 indicates that the post operator wants to execute the statement using the original value; <br>alert(a);//Output 2 indicates that the post operator executes the original value before executing the statement. Change the value; <br>alert( b); // Output 1; <br>alert(c); // Output NaN; <br>alert(d); // Output -1; <br></ script> <br> </div>