two-times.js

这是《JavaScript学习源代码》一书的源代码

// create a counter variable and a timer variable
var num = 0, tim;
function timeout()
{                                  
  num++;                                             
  if( num == 3 )
  {                                        
    alert("OK - I told you twice");
    window.clearTimeout( tim );    // cancel the timer                    
  } 
  else 
  {                                           
    alert("This is 10-Second Message No : " + num ); 
    tim = window.setTimeout( "timeout()" , 10000); }            }
timeout();