Question

我想使用带if条件的JavaScript检查变量中的值。在这些情况下，变量location的值为var location="Banglore"。但每次去其他地方。

我的代码是

  var location="Banglore";
  if(typeof(location)== "Bangalore")
   {
      var data_file = "http://api.openweathermap.org/data/2.5/
      find?      q=Bangalore&units=metric";
   }
  else if(typeof(location) == "Chennai")
   {
      var data_file = "http://api.openweathermap.org/data/2.5/
      find?q=Chennai&units=metric";
   }
 else if(typeof(location) == "Cochi")
   {
      var data_file = "http://api.openweathermap.org/data/2.5/
      find?  q=Cochi&units=metric";
   }
 else 
   {
      var data_file = "http://api.openweathermap.org/data/2.5/
      find?q=Pune&units=metric";
   }

在这些代码中总是转到其他部分，即location == pune condition.Any body帮助我

Answer 1

问题是你有错误的检查值。

var location="Banglore";
  if(location == "Bangalore") // extra `a` after `g`
   {
      var data_file = "http://api.openweathermap.org/data/2.5/
      find?      q=Bangalore&units=metric";
   }
  else if(typeof(location) == "Chennai") // typeof gives here "string" as result
      //so your condition evaluates as
      // "string" == "Chennai", and so on for the rest,
      // hence it always goes to else block
   {
      var data_file = "http://api.openweathermap.org/data/2.5/
      find?q=Chennai&units=metric";
   }

也不要在本地块中声明变量，如果你要在给定的块之外使用它，这里是data_file在if..else块内声明。

Answer 2

首先，你要比较错误的语法，

var location="Banglore";
  if(location == "Bangalore") // this should be location == "Banglore"
   {

第二件事是，

为什么使用typeof()检查其他城市？据我所知，你应该使用

var location="Banglore";
  if(location == "Banglore")
   {
      var data_file = "http://api.openweathermap.org/data/2.5/
      find?q=Bangalore&units=metric";
   }
  else if(location == "Chennai")
   {
      var data_file = "http://api.openweathermap.org/data/2.5/
      find?q=Chennai&units=metric";
   }
 else if(location == "Cochi")
   {
      var data_file = "http://api.openweathermap.org/data/2.5/
      find?q=Cochi&units=metric";
   }
 else 
   {
      var data_file = "http://api.openweathermap.org/data/2.5/
      find?q=Pune&units=metric";
   }

注意：您可能还必须删除查询中的空格。

Answer 3

你应该使用switch语句，这就是它的意思......

var location = "Banglore",
    data_file = "http://api.openweathermap.org/data/2.5/find?units=metric&q=";

switch (location) {
    case "Bangalore":
        data_file += "Bangalore";
        break;
    case "Chennai":
        data_file += "Chennai";
        break;
    case "Cochi":
        data_file += "Cochi";
        break;
    default:
        data_file += "Pune";
}

Answer 4

您正在将位置设置为＆＃39; Banglore＆＃39;和＆＃39;如果＆＃39;条件是＆＃39;班加罗尔＆＃39;。

使用javascript检查变量中的值

4 个答案: