$ .ajax从PHP文件获取返回值

Question

here I have jQuery ajax calling a .php file that SOMETIMES executes let's say the following

echo "hello"

Here it is:

    $.ajax({
        type: "POST",
        url: myurl.php
        data: data_string,
        timeout: 6000,
        success: function () {

        }
    });

I would like to know: is it possible to make the ajax return ERROR and not SUCCESS when something like the previous echo is executed in the PHP file? I mean, checking inside this $.ajax if the php file is executed as I would or not.

EXPLAINING BETTER: I get error when the request could not be completed and success when it could. But I would like to get like a return value from this PHP file. If it returns 1, I wanna do something. If it returns 2, instead, I wanna do something else. Hope I explained it better..

Thanks in advance.

Answer 1

I recommend using json_encode() within your PHP file. For example:

echo json_encode(array('success' => 'do_foo'));
exit();

Then you can add a conditional within the success callback:

$.ajax({
  type: "POST",
  url: myurl.php
  data: data_string,
  dataType: "JSON", //tell jQuery to expect JSON encoded response
  timeout: 6000,
  success: function (response) {
    if (response.success === 'hello'){
      console.log(response);
    } else {
      console.log('else');
    }
  }
});

Answer 2

Based on your question make php return 1 or return 2. You can make it return 1 on failure and 0 (which is null) on success. Then you can do this for your ajax return.

$.ajax({
                type: "POST",
                url: "YOUR URL",
                data: dataString,
                success: function(server_response)
                    {
                        if(server_response == 1)
                        {
                            alert("You have made a mistake");
                            return true;
                        }

                        HERE YOU WILL PUT WHAT HAPPENS ON SUCCESS

                        }
                    });

Answer 3

$.ajax({
    type: "POST",
    url: myurl.php
    data: data_string,
    timeout: 6000,
    success: function (msg) {
       if (msg != "Hi")
       {
          //TODO
       } else
       {
          //TODO
       }
    }
});

Answer 4

You can use error callback for this:

$.ajax({
    type: "POST",
    url: myurl.php
    data: data_string,
    timeout: 6000,
    success: function () {

    },
    error: function() {
        /* Code reacting to error here */
    }
});

Also, there are other callback opportunities which you can check out at $.ajax documentation page .

If you are going to "say" fron PHP that there is an error, this can be done with 2 ways:

You can print in PHP a keyword meaning an error and then check it in you success function:

success: function (data) {
    if (data == 'error') {
    } else {
    }
}

Or, the other way, you can provide with PHP right headers to cause "error". Then you can use the error callback as usual. I would choose this way.