AJAX/JQuery success:/error: function manipulation

Question

Having some trouble with AJAX/JQuery. Here is the context of my problem followed by a code sample:

What I am attempting to do is call a PHP script called getInfo.php and check whether or not some data is contained within a database. I can write queries easily enough but in terms of the code sample below how can I "tell" the success function to fail if it cannot find data in the database and run the error function instead?

$(document).ready(function(){
        getInfo();
        function getInfo(){
            $.ajax({
                type: "GET",
                url: "getInfo.php",
                data: "do=getInfo",
                cache: false,
                async: false,
                success: function(result) {
                    $("#myInfo").remove();
                    alert("Data found");
                },
                error: function(result) {
                    alert("Data not found");
                }
            });
        }
});

Any advice would be greatly appreciated. =)

Answer 1

The error handler is used to handle errors in your AJAX call.

You could echo 1 in your PHP script if the data was found and 0 if it was not found. Then you could use an if statement to determine what to do. For example:

success: function(result)
{
    if(result == 1)
    {                    
        $("#myInfo").remove();
        alert("Data found");
    }
    else
    {
        alert("Data not found");
    }
},

Answer 2

"success" gets called when the returned code is a "200" (successfull request). "error" gets called whenever another code is returned (e.g. 404, 500).

So I think you can do 2 things:

• Let PHP return a 404 so the error function gets called

• Let your getinfo.php return a boolean value (usually my approach)

  {"success":true, ...}