嵌套的 if else 语句仅适用于第一条语句

Question

我对嵌套的 if else 语句有疑问。在这个问题中，它只执行第一个 if 语句并跳过所有其余的，当我想要执行每个语句时。 else if 语句在其中没有嵌套任何内容时工作正常，但是当我嵌套其他 if else 语句时，只有第一个似乎工作。这是我的 javascript 代码：

const apiURL2 = "https://api.openweathermap.org/data/2.5/forecast?id=5604473&appid=6d1d830097a2c0bac1aba2337d0139e6";

fetch(apiURL2).then((response) => response.json()).then((jsonObject) => {
const list = jsonObject['list'];
console.log(jsonObject);
for ( let i = 0; i < 5; i++){

    let divForecastData = document.querySelector('div.weather-forecast-wrapper');
    let temp1 = document.createElement("div");
    let tempday = document.createElement("p");
    let temperature = document.createElement("p");
    let icon = document.createElement("i");
    
    temperature.className = "temp";
    tempday.className = "weekday";
    temp1.className = "day";

    if (i == 0){
      tempday.textContent = "Sat";
      temperature.textContent = list[i].main.temp;
      if (list[i].weather[i].main = "Clear"){
        icon.className = "worked"
      }
      else {
        icon.className = " still worked"
      }
      
    }
    else if (i == 1){
      tempday.textContent = "Sun";
      var far = list[i].main.temp
      var kel = far * (9/5) - 459.67;
      temperature.textContent = Math.round(kel) + "℉";
      if (list[i].weather[i].main = "Clear"){
        icon.className = "worked"
      }
      else {
        icon.className = " still worked"
      }
      
    }
    else if (i == 2){
      tempday.textContent = "Mon";
      temperature.textContent = list[i].main.temp;
    }
    else if (i == 3){
      tempday.textContent = "Wed";
      temperature.textContent = list[i].main.temp;
    }
    else{
      tempday.textContent = "Thu";
      temperature.textContent = list[i].main.temp;
      
    }


    divForecastData.appendChild(temp1);
    temp1.appendChild(tempday);
    temp1.appendChild(icon);
    temp1.appendChild(temperature);
    

}






  });

有什么建议吗？

Answer 1

比较用 == 或 ===...

编码

所以这样不好。 if (list[i].weather[i].main = "Clear")

但是 list[i].weather[i] 有些东西不存在，我知道是因为运行代码会在控制台上显示一条红色的大消息。您可能想使用 list[i].weather[0].

这是更正后的代码片段

const apiURL2 = "https://api.openweathermap.org/data/2.5/forecast?id=5604473&appid=6d1d830097a2c0bac1aba2337d0139e6";

fetch(apiURL2).then((response) => response.json())
.then((jsonObject) => {
    let divForecastData = document.querySelector('div.weather-forecast-wrapper');
    
    console.log(jsonObject);
    
    const list = jsonObject['list'];

    for ( let i = 0; i < 5; i++){
        const item = list[i];
        
        let temp1 = document.createElement("div");
        let tempday = document.createElement("p");
        let temperature = document.createElement("p");
        let icon = document.createElement("i");

        temperature.className = "temp";
        tempday.className = "weekday";
        temp1.className = "day";

        if (i == 0){
            tempday.textContent = "Sat";
            temperature.textContent = item.main.temp;
            if (item.weather[i].main = "Clear"){
                icon.className = "worked"
            } else {
                icon.className = " still worked"
            }
        } else if (i == 1){
            tempday.textContent = "Sun";
            var far = item.main.temp
            var kel = far * (9/5) - 459.67;
            temperature.textContent = Math.round(kel) + "℉";
            if (item.weather[0].main === "Clear"){
                icon.className = "worked"
            } else {
                icon.className = " still worked"
            }
        } else if (i == 2){
            tempday.textContent = "Mon";
            temperature.textContent = item.main.temp;
        } else if (i == 3){
            tempday.textContent = "Wed";
            temperature.textContent = item.main.temp;
        } else{
            tempday.textContent = "Thu";
            temperature.textContent = item.main.temp;
        }

        divForecastData.appendChild(temp1);
        temp1.appendChild(tempday);
        temp1.appendChild(icon);
        temp1.appendChild(temperature);
    }
});

<div class='weather-forecast-wrapper'></div>

嵌套的 if else 语句仅适用于第一条语句

Nested if else statements only works on first statement

javascript

if-statement

boolean

nested