获取当前地址

/*获取当前位置start*/
function getLocation(elem)
{
    if (navigator.geolocation)
    {
        //navigator.geolocation.getCurrentPosition(function(position){
        var geolocation = new BMap.Geolocation();
        geolocation.getCurrentPosition(function(position){
            //var W_ = position.coords.latitude;//维度
            //var J_ = position.coords.longitude;//经度
            var W_ =position.point.lat;
            var J_ =position.point.lng;
            Select(W_,J_,elem);
        });
    }
    else{
        alert("无法获取当前位置");
    }
}
var SAMPLE_POST_REVERSE = 'https://api.map.baidu.com/geocoder/v2/?ak=密钥&callback=renderReverse&s=1';
var safe = '';
var pois;
function showReverseURL(latitude,longitude,elem)
{
    safe = SAMPLE_POST_REVERSE;
    safe += "&location=" + latitude + "," + longitude;
    safe += "&output=json";
    safe += '&pois=' + pois;

};

function Select(latitude,longitude,elem)
{
    var script = document.createElement('script');
    script.type = 'text/javascript';
    showReverseURL(latitude,longitude,elem);
    var newURL = safe.replace('密钥', '密钥值');
    script.src = newURL;
    document.body.appendChild(script);
};

function renderReverse(response)
{
    var val = '';
    if (response.status)
    {
        alert("无正确的返回结果");
        return;
    }
    var location = response.result.location;
    if(response.result.formatted_address == "")
    {
        alert("无正确的返回结果");
    }
    else
    {
        val=response.result.formatted_address+response.result.sematic_description;
    }

    if (pois == 1)
    {
        val="";
    }
    window.elem.val(val);

//  $("#address").val(val);
    return;
}
/*获取当前位置end*/