设置 JQuery event.preventDefault() 时绕过 window.open 上的弹出窗口阻止程序

Popup blockers will typically only allow window.open if used during the processing of a user event (like a click). In your case, you're calling window.open later, not during the event, because $.getJSON is asynchronous.

You have two options:

1. Do something else, rather than window.open.

2. 使Ajax调用同步，这通常是您应该避免的，因为它锁定了浏览器的UI.$.getJSON相当于:

   $.ajax({
     url: url,
     dataType: 'json',
     data: data,
     success: callback
   });
   

   ...and so you can make your $.getJSON call synchronous by mapping your params to the above and adding async: false:

   $.ajax({
       url:      "redirect/" + pageId,
       async:    false,
       dataType: "json",
       data:     {},
       success:  function(status) {
           if (status == null) {
               alert("Error in verifying the status.");
           } else if(!status) {
               $("#agreement").dialog("open");
           } else {
               window.open(redirectionURL);
           }
       }
   });
   

   Again, I don't advocate synchronous ajax calls if you can find any other way to achieve your goal. But if you can't, there you go.

   以下是由于异步调用而导致测试失败的代码示例:

   Live example | Live source (The live links no longer work because of changes to JSBin)

   jQuery(function($) {
     // This version doesn't work, because the window.open is
     // not during the event processing
     $("#theButton").click(function(e) {
       e.preventDefault();
       $.getJSON("http://jsbin.com/uriyip", function() {
         window.open("http://jsbin.com/ubiqev");
       });
     });
   });
   

   下面是一个使用同步调用确实有效的示例:

   Live example | Live source (The live links no longer work because of changes to JSBin)

   jQuery(function($) {
     // This version does work, because the window.open is
     // during the event processing. But it uses a synchronous
     // ajax call, locking up the browser UI while the call is
     // in progress.
     $("#theButton").click(function(e) {
       e.preventDefault();
       $.ajax({
         url:      "http://jsbin.com/uriyip",
         async:    false,
         dataType: "json",
         success:  function() {
           window.open("http://jsbin.com/ubiqev");
         }
       });
     });
   });