涉及AJAX的函数不返回值 - jQuery [重复]

Question

This question already has an answer here:

• How do I return the response from an asynchronous call? 35 answers

I have a document.ready function like this;

  function myfun(){
    var xx;
    $.ajax({
        type: 'POST',
        url: 'handler.php',
        cache: false,
        success: function(result) {
          xx = result;
        },
    });
    return xx;
  }


  var a;
  a = myfun();
  alert(a);

handle.php is set to echo 1234. But I am getting alert as "undefined". How can I fix this? Expected alert is "1234" (the reply from ajax handler).

</div>

Answer 1

It's asynchronous. Use a callback:

function myfun(){

    return $.ajax({
        type: 'POST',
        url: 'handler.php',
        cache: false
    });
}

myfun().done(function(data){
    console.log(data);
});

Or if you're using an old jQuery version without deferred objects:

function myfun(done){

    $.ajax({
        type: 'POST',
        url: 'handler.php',
        cache: false,
        success: done
    });
}

myfun(function(data){
    console.log(data);
});

https://stackoverflow.com/search?q=ajax+not+returning+data