JS的function 返回值问题 求解

Question

JSJson.NET

Answer 1

categories:// ['10:18:13','10:20:11','10:21:03','10:53:08','10:55:14','10:56:16','10:57:21','10:58:29','10:59:33','11:10:33'],
                        function () {
                        $.get("ashx/Handler.ashx", { time: new Date().getTime() }, function (data) {
                            alert(data);
                            var dd = "{root:" + data + "}";
                            var dobj = eval("(" + dd + ")");
                            var x = eval("(" + data + ")");
                            var text="[";
                            var dataarry = new Array(dobj.root.length);
                            for (var i in x) {                                
                                dataarry[i]=x[i].postdate;
                                text+="'"+x[i].postdate+"'";
                                if(i!=dobj.root.length-1)
                                {
                                    text+=",";
                                }
                            }
                            text+="]";
                            alert(text); 
                            return text;                           
                        })                        
                    }

Answer 2

我第一行注释了的数组就是最后alert（text）弹出的数组，我直接贴数组可以使用，用return text就不行 ，不知道是不是有语法错误..

Answer 3

把你要这个返回数据的方法写到ajax里  ajax是异步执行的  所以如果再外边接收的话很可能在接收时ajax还没返回数据呢  所以接收不到

Answer 4

return text;  给谁用。

Answer 5

return 的东西不是用在for ( ; list && firingIndex < firingLength; firingIndex++ ) {
var $a = list[ firingIndex ];
if ( $a.apply( data[ 0 ], data[ 1 ] ) === false && options.stopOnFalse ) {
memory = false; // To prevent further calls using add
break;
}
}

Answer 6

text 在function外 申明var text;
function x(){
    $.ajax( , function( data ){
        return ( text = data );
    });
}

Answer 7

text 在function外 申明var text;
function x(){
    $.ajax( , function( data ){
        return ( text = data );
    }, false );
}

Answer 8

tooltip: {
                    enabled: true,
                    formatter: function() {
                        return '<b>' + this.x + '</b><br/>' + this.series.name + ': ' + Highcharts.numberFormat(this.y, 1);
                    }

Answer 9

这是对象的方法，当然要有返回值。可你那个是回调函数，要返回值 返回给谁？
$.get()的回调函数是不需要返回值，
说下你那个text是要用来干什么的

Answer 10

你确定这里的categories可以接受函数吗？如果不能，那么你可以这么做，将ajax设置为同步，然后
categories:function(){你的内容}();
意思是定义一个函数，并执行该函数

Answer 11

ajax是异步执行的，你把它改成$.ajax（）方法的同步试一下看

Answer 12

categories:function(){
var value = '';
$.ajax({
url:'ashx/Handler.ashx',
async:false,//设置为同步,
data:{ time: new Date().getTime() },
success:function(data){
alert(data);
var dd = "{root:" + data + "}";
var dobj = eval("(" + dd + ")");
var x = eval("(" + data + ")");
var text="[";
var dataarry = new Array(dobj.root.length);
for (var i in x) {                                
dataarry[i]=x[i].postdate;
text+="'"+x[i].postdate+"'";
if(i!=dobj.root.length-1){
text+=",";
}
}
text+="]";
alert(text); 
value=text;
}
});
return value;
}()

Answer 13

我按照这个方法写了，代码可以正常执行，alert也可以弹出数据但是效果没出来我把效果贴出来

Answer 14

<script type="text/javascript">        var chart;
        $(document).ready(function() {
            chart = new Highcharts.Chart({
                chart: {
                    renderTo: 'container',          //放置图表的容器
                    plotBackgroundColor: null,
                    plotBorderWidth: null,
                    defaultSeriesType: 'line'
                },
                title: {
                    text: '气温走势'
                },
                subtitle: {
                    text: '测试仪'
                },
                xAxis: {//X轴数据
//                    categories:// ['10:18:13','10:20:11','10:21:03','10:53:08','10:55:14','10:56:16','10:57:21','10:58:29','10:59:33','11:10:33'],
                      categories:function(){
                                var value = '';
                                $.ajax({
                                    url:'ashx/Handler.ashx',
                                    async:false,//设置为同步,
                                    data:{ time: new Date().getTime() },
                                    success:function(data){
                                        alert(data);
                                        var dd = "{root:" + data + "}";
                                        var dobj = eval("(" + dd + ")");
                                        var x = eval("(" + data + ")");
                                        var text="[";
                                        var dataarry = new Array(dobj.root.length);
                                        for (var i in x) {                                
                                            dataarry[i]=x[i].postdate;
                                            text+="'"+x[i].postdate+"'";
                                            if(i!=dobj.root.length-1){
                                                text+=",";
                                            }
                                        }
                                        text+="]";
                                        alert(text); 
                                        value=text;
                                    }
                                });
                                return value;
                            }(),
                    labels: {
                        rotation: -45, //字体倾斜
                        align: 'right',
                        style: { font: 'normal 13px 宋体' }
                    }
                },
                yAxis: {//Y轴显示文字
                    title: {
                        text: '温度/℃'
                    }
                },
                tooltip: {
                    enabled: true,
                    formatter: function() {
                        return '<b>' + this.x + '</b><br/>' + this.series.name + ': ' + Highcharts.numberFormat(this.y, 1);
                    }
                },
                plotOptions: {
                    line: {
                        dataLabels: {
                            enabled: true
                        },
                        enableMouseTracking: true//是否显示title
                    }
                },
                series: [{
                    name: '温度',
//                    data:[13.00,14.00,14.21,15.00,15.50,16.00,19.00,18.70,17.10,14.00]
                    data:function(){
                    var value = '';
                    $.ajax({
                        url:'ashx/Handler.ashx',
                        async:false,//设置为同步,
                        data:{ time: new Date().getTime() },
                        success:function(data){
                            alert(data);
                            var dd = "{root:" + data + "}";
                            var dobj = eval("(" + dd + ")");
                            var x = eval("(" + data + ")");
                            var text="[";
                            var dataarry = new Array(dobj.root.length);
                            for (var i in x) {                                
                                dataarry[i]=x[i].intvalue;
                                text+=x[i].intvalue;
                                if(i!=dobj.root.length-1){
                                    text+=",";
                                }
                            }
                            text+="]";
                            alert(text); 
                            value=text;
                        }
                    });
                    return value;
                }()
                    
                }]
                });
            }); 
    </script>这个是那JS的所有代码

Answer 15

最终效果：
现在效果：我写那个function就是为了得到categories: ['10:18:13','10:20:11','10:21:03','10:53:08','10:55:14','10:56:16','10:57:21','10:58:29','10:59:33','11:10:33']，

Answer 16

跟回调函数没关系，直接 url返回数据就可以了吧

Answer 17

插件地址...http://www.cnblogs.com/xyzxzh2009/archive/2012/04/06/2434065.html
json解析什么的都才开始学.....

Answer 18

LZ  遇到没效果 一般先检查2个问题  
1、数据类型
LZ的function；里面是用字符串拼接的。。   你查查你返回的数组是什么类型  我猜是字符串..2、实现代码问题 不多说。。

Answer 19

LZ刚接触JSON   给个建议json是json   字符串是字符串   

Answer 20

没效果是必然的。 return value; 时，那ajax的值还没到。

Answer 21

1.先用ajax取到數據，然后創建圖表對象，同時把數據傳給對象
2.摟收的數據是字符串，還是數組要搞清楚，你return text的是字符串，categories的值要求是數組
$.ajax({
    url: 'xxx',
    success: function(data) {
        var text = [];
        ...
        var chart = new Highcharts.Chart({
            ...
            categories: text;
            ...
        });
    }
});

Answer 22

看清楚再说，ajax使用的同步模式，懂么？
出现楼主所说的问题，应该是value的值是字符串造成的。将return value 改为 return eval('('+value+')')(意思是将字符串转化为对象);试试看。

Answer 23

顶32楼！那些叫LZ把异步改同步的，都好坏哦~~，那还不如让LZ叫后端的同事在html生成的时候一并查出数据来输出算了。伦家用异步就是为了表格数据的加载和页面加载分离，提高用户体验的说。这下子又换成同步加载了，异步的优势都木有了。32楼才是正解呢。LZ把ajax请求和new Highcharts的代码顺序弄颠倒了。正确的做法应该是先ajax异步请求，在回调中拿到数据后再new Highcharts。可惜是异步，return搞不定，因为时空都错乱了，so，ajax回调再new Highcharts才是正解，异步改同步是偏方啊！