Question

如何使返回值为true和false。

我总是未定义，在阅读了一些文章之后，我仍然不理解。

我的参考：How to return value from an asynchronous callback function?

            function validateScreenName(value){
            var screenname = document.getElementById("screenname-box").value;

            if((screenname.length < 3) || (screenname.length > 20)){
                value(false); // if I change to return false still can't get the value. Always undefined.
            }else{
                if(screenname != "something"){
                    var http = new XMLHttpRequest();
                    var param = "screen_name="+screenname;

                    var url = "screen-name-validation.php";
                    http.open("POST",url,true);
                    http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

                    http.onreadystatechange = function(){
                    //The response from server is either 1 or 0
                        if (http.readyState==4 && http.status==200){
                            if(http.responseText == 0){
                                value(true); // I can't get this value
                            }else{
                                value(false);
                            }
                        }
                    }
                    http.send(param);
                }else{
                    value(false);
                }
            }
        }

我需要这个脚本的值

            function disableSubmit(){

            validateScreenName(function(val2){
               var val1 = validateFullName();
               var val3 = validateTargetName();
               //I need val2 from validateScreenName
               if(val1 && val2 && val3){
                   //if all true do something
               }else{
                   //if one of the value false do somthing
               }
            });         
        }

有人可以解释如何在没有jquery的情况下仅使用javascript获取值吗？感谢。

Answer 1

不使用返回typeof bool（false，true），而是使用返回string..eg。，“true”或“false”

如何从ajax返回值

1 个答案: