Javascript值不分配

Question

我在此处指定了place id“placeid = results [0] .place_id”但它没有设置。它返回给我未定义。分配操作在那里失败。

function match_up_dn(address) 
{ 
    geocoder = new google.maps.Geocoder(); 
    var placeid; 

    if (geocoder) 
    { 
     geocoder.geocode({ 
      'address': address 
     }, function (results, status) { 

      if (status == google.maps.GeocoderStatus.OK) { 
       console.log("al:-"+results[0].place_id); 
       placeid = results[0].place_id; 
      } 
      else 
      { 
       alert("undefined address"); 
      } 
     }); 
    } 

    return placeid; 
} 

Answer 1

试试这个

function match_up_dn(address) 
{ 
    geocoder = new google.maps.Geocoder(); 
    var placeid; 

     geocoder.geocode({ 
      'address': address 
     }, function (results, status) { 

      if (status == google.maps.GeocoderStatus.OK) { 
       console.log("al:-"+results[0].place_id); 
       placeid = results[0].place_id; 
       return placeid; 
      } 
      else 
      { 
       alert("undefined address"); 
      } 
     }); 

}