Question

如何在每個對象中循環字符串添加到像下面的結果一樣的字符串？
我需要將每個變量this_encode添加到一個字符串，該怎麼做？

result: '<img src=""><iframe></iframe><img src="">'

for (var key in obj) { 
    if (obj[key].file_type == 0) { 
     var this_encode = '<img src="' + obj[key].file_name + obj[key].file_format + '">'; 
    } else if(obj[key].file_type == 1) { 
     var this_encode = '<iframe width="150" height="100" src="'+obj[key].file_embed_url +'" frameborder="0" allowfullscreen></iframe>'; 
    } 
} 

OBJ

file_embed_url: "" 
file_format: "jpg" 
file_name: "53b21c90dded9" 
file_sequence: "0" 
file_type: "0" 
gallery_id: "1" 
id: "138" 

file_embed_url: "//www.youtube.com/embed/-x6jzKpqeuw" 
file_format: "" 
file_name: "" 
file_sequence: "1" 
file_type: "1" 
gallery_id: "1" 
id: "139" 

... 

Answer 1

聲明你this_encode變量外循環，然後用連接來創建一個字符串

// first initialise your variable as an empty string; can't concatenate to undefined 
var this_encode = ''; 

// Now run your code as before with 2 small differences 
//  (1) Remove the var declarations 
//  (2) Use += instead of = to indicate that you want to append the following text to the this_encode variable 
for (var key in obj) { 
    if (obj[key].file_type == 0) { 
     this_encode += '<img src="' + obj[key].file_name + obj[key].file_format + '">'; 
    //^  ^see the change here 
    // | 
    // var declartion removed from here (and below) 
    } else if(obj[key].file_type == 1) { 
     this_encode += '<iframe width="150" height="100" src="'+obj[key].file_embed_url +'" frameborder="0" allowfullscreen></iframe>'; 
     //  ^and here 
    } 
}