如果 API 请求给出字符串，如何告诉 JS 仅替换 HTML？

Question

I want JS to fill my span only if API gave an actual string for both fields. If it didn't then I want it to display default value only in one field. The default value is "Germany".

Here is my code:

$(document).ready(function () {
  $.get("https://api.ipdata.co?api-key=[APIKEY]", function (response) { 
    city = response.city;
    country_name = response.country_name;
    $("#city").html(city);
    $("#country_name").replaceWith(country_name);
  }, "jsonp"); 
});

<span id="city"></span>
<span id="country_name">Germany</span>

Answer 1

Firstly you should use text() not replaceWith() to set the innerText of the div . Secondly, you can use || to coerce a value if it's undefined , null , an empty string or any other falsy value. Try this:

$("#city").text(city || '');
$("#country_name").text(country_name || 'Germany');

Answer 2

If you want to populate both fields only if both fields are returned from the ajax request, you can simply wrap them in an if statement:

$.get("...api.site.here", function(response){

 if(response.city && response.country_name){
  // same code here
 }

}