如何调试jQuery POST AJAX操作？

Question

I want the data coming from the server to show in the <div id="demo"> element.

But sometimes, it just appears and goes, and other times, it is not even showing up. I searched and tried lots of options, but nothing works for me.

My code is:

 function loadDoc(){     
   document.getElementById("demo").innerHTML = "Paragraph changed!";
   alert("hello world");
   $.ajax({
     type:'POST',
     url :"new_mark.php",
     data :"regno=u4cse13xxx",
     success: function(data) {          
        //$("demo").html = "Narayana!";
        document.getElementById("demo").innerHTML = data;
        alert(data);
     }
   });
 }

Answer 1

To debug an web site, i advise you tu use the Chrome debugger or on generaly the browser debugger its very simple and usefull.

Click F12 and go to ressources and put an debug point at your line and it finished

Answer 2

Just call the Element and set the the content via a jquery method like text (Reference: .text() )

So your code inside success would be:

success: function(data) {          
    $("#demo").text(data);
 }

And maybe you can tell me if it worked? :) Greets!

Answer 3

Go to the Network tab of the debugger, select your request (new_mark.php), then check the Response tab. If there was an error, it should appear in the response.

For example in Chrome: