为什么我不能从 Ajax 函数返回 responseText? [英] Why can I not return responseText from an Ajax function?

问题描述

这是我的 Ajax 函数的一部分.由于某种我无法弄清楚的原因，我可以alert() responseText 但不能return responseText.有人可以帮忙吗?我需要在另一个函数中使用该值.

Here is part of my Ajax function. For some reason that I cannot figure out, I am able to alert() responseText but not able to return responseText. Can anybody help? I need that value to be used in another function.

http.onreadystatechange = function(){
    if( http.readyState == 4 && http.status == 200 ){
        return http.responseText;
    }
}

推荐答案

您将无法处理从异步回调返回的返回值.你应该直接在回调中处理responseText，或者调用一个辅助函数来处理响应:

You will not be able to handle the return value that you are returning from your asynchronous callback. You should handle the responseText within the callback directly, or call a helper function to handle the response:

http.onreadystatechange = function () {
    if (http.readyState == 4 && http.status == 200) {
        handleResponse(http.responseText);
    }
}

function handleResponse (response) {
    alert(response);
}

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