将Ajax调用到httpstatusready = 4不执行

Question

我正在使用ajax - 工作正常 - 传递该值。但是当我添加HTTP代码时，没有任何操作。使用简单的HTTP根据http.readystatus显示不同的div值。这是正确的格式吗？如果不是，那是什么？

if (colorToCheck == gup("Player1")) { 
    document.getElementById('win').innerHTML = player1 + " wins"; 
    redScore += 1; 

    //Browser Support Code 
    var xmlhttp; 
    if (window.XMLHttpRequest) { 
     // code for IE7+, Firefox, Chrome, Opera, Safari 
     xmlhttp = new XMLHttpRequest(); 
    } else { 
     // code for IE6, IE5 
     xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); 
    } 
    if (xmlhttp.readyState == 3 && xmlhttp.status == 200) { 
     document.getElementById("save").innerHTML = "saving"; 
    } else if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { 
     //ajax call 
     var dataString = 'winner=' + player1 + '&player1=' + player1 + '&player2=' + player2 + '&matchNum=' + matchNum; 
     $.ajax({ 
      type: "POST", 
      url: "red.php", 
      data:dataString, 
      cache: false, 
      success: function(response) { 
       $('.result13').html(response);  
      } 
     }); 
    } 
} 

任何帮助将不胜感激！提前致谢。

Answer 1

一个Vanilla JS AJAX调用的结构是：

var xmlhttp = new XMLHttpRequest(); 
xmlhttp.open("GET","path/to/file.php"); // or "POST" if needed 
xmlhttp.onreadystatechange = function() { 
    if(this.readyState == 3) document.getElementById('save').innerHTML = "saving"; 
    if(this.readyState == 4) { 
     if(this.status != 200) alert("ERROR: Server returned "+this.status+" "+this.statusText); 
     else { 
      // do something 
      alert(this.responseText); 
     } 
    } 
}; 
xmlhttp.send(data); // data is whatever POST data you want. Leave out if using GET.