高德js API根据出行方式和出现策略由起始点经纬度实现路线规划

<!doctype html>
<html>
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no, width=device-width">
    <title>路线规划</title>
    <link rel="stylesheet" href="https://cache.amap.com/lbs/static/main.css"/>
    <script type="text/javascript" src="js/jquery-1.10.2.js" ></script>
    <script type="text/javascript" src="https://webapi.amap.com/maps?v=1.4.0&key=5bffad5c5d7992363d1eb9518dcc3e9d"></script>
</head>
<body>
<div id="mapContainer"></div>
<div id="panel"></div>
<script type="text/javascript">
    window.onload=function(){
        getRoad("Driving","最短距离模式",[103.912339,30.755537],[103.920859,30.757879]);
  };

    //规划不同的导航路线
    function getRoad(type,way,lnglat1,lnglat2){
        var map = new AMap.Map("mapContainer", {
            resizeEnable: true
        });
        //路线规划策略
        var policy=function(){
            switch(type){
                case "Driving": switch(way){
                    case "考虑实时路况" : return AMap.DrivingPolicy.REAL_TRAFFIC;break;          //考虑实时路况
                    case "最经济模式" : return AMap.DrivingPolicy.LEAST_FEE; break;              //最经济模式
                    case "最短距离模式" : return AMap.DrivingPolicy.LEAST_DISTANCE; break;       //最短距离模式
                    default : return AMap.DrivingPolicy.LEAST_TIME;break;                       //最快捷模式
                };
                break;
                case "Transfer": switch(way){
                    case "最经济模式" : return AMap.TransferPolicy.LEAST_FEE; break;            //最经济模式
                    case "最少换乘模式" : return AMap.TransferPolicy.LEAST_TRANSFER; break;     //最少换乘模式
                    case "最少步行模式" : return AMap.TransferPolicy.LEAST_WALK; break;         //最少步行模式
                    case "最舒适模式" : return AMap.TransferPolicy.MOST_COMFORT; break;         //最舒适模式
                    case "不乘地铁模式" : return AMap.TransferPolicy.NO_SUBWAY; break;          //不乘地铁模式
                    default : return AMap.TransferPolicy.LEAST_TIME ;break;                    //最快捷模式
                    };
                break;
                default : break;
                }
            };
        AMap.service(["AMap."+type], function() {
        var transOptions = {
            map: map,
            panel:panel,
            city: "成都市",
            policy: policy()
        };
        var trans;
        switch(type){
            case "Driving": trans = new AMap.Driving(transOptions);break;
            case "Walking": trans = new AMap.Walking(transOptions);break;
            case "Riding": trans = new AMap.Riding(transOptions);break;
            default: trans = new AMap.Transfer(transOptions);break;
        }
        //根据起、终点坐标查询公交换乘路线
        trans.search(lnglat1, lnglat2, function(status, result){});
    });
    }
</script>
</body>
</html>