Question

为什么javascript不生成函数的输出？

var name = prompt("What is your name?");
var weight = prompt("what is your weight?");
function check(name ,weight){
       if (weight> 25) {
           alert (name + "Your weight is " + weight + "which is not normal."+ "Sorry");
       }
       else {
           alert (name + "Your weight is " + weight + "which is normal." + "Welcome");
       }

    return check;
}check;
</script>

Answer 1

因为它格格不入，所以你甚至不能结束这项功能。

你必须返回一个值才能返回任何值。

也许这就是你想要实现的目标：

var name = prompt("What is your name?");
var weight = prompt("what is your weight?");

function check(name ,weight){
  if (weight> 25) {
     return name + "Your weight is " + weight + "which is not normal."+ "Sorry";
  } else {
     return name + "Your weight is " + weight + "which is normal." + "Welcome";
  }
}

alert(check(name, weight));

注意我如何将参数name和weight传递给check - 函数

Answer 2

应该是这样的：

       var name = prompt("What is your name?");
       var weight = prompt("what is your weight?");

       function check(name ,weight){
           if (weight> 25) {
               alert (name + "Your weight is " + weight + "which is not normal."+ "Sorry");
           }
           else {
               alert (name + "Your weight is " + weight + "which is normal." + "Welcome");
           }
        return true;               // check is invalid
       }                           // you forgot to close it
       check(name,weight);          // calling the function

Answer 3

声明函数时，您将声明参数：名称和重量。这些参数只能在该函数的范围内使用。看起来您正试图将它们设置在范围之外。然后你返回变量检查。哪个是空的。此外，您还没有从函数外部调用函数，因此函数check（）永远不会被触发。

这是一个例子（live example）：

var input1="peter"; input2=10;
check(input1, input2);
function check(name, weight) {
    var check;
    if (weight < 25) { //true
        check = "Text"+name;
    } else {
        check = "No text"+name;
    }
    return alert(check);
}

PS：尚未测试此代码。

Answer 4

该函数需要外部调用来执行操作。因此，如果您想以上述方式显示结果，请添加

   function check(name ,weight){
       if (weight> 25) {
           alert (name + "Your weight is " + weight + "which is not normal."+ "Sorry");
       }
       else {
           alert (name + "Your weight is " + weight + "which is normal." + "Welcome");
       }
       return true;               
   }

   check(name,weight);

或者你可以通过其他方式调用它

<p id="print"></p>
<script>
    function check(name ,weight){
        if (weight> 25) {
           alert (name + "Your weight is " + weight + "which is not normal."+ "Sorry");
        }
        else {
           alert (name + "Your weight is " + weight + "which is normal." + "Welcome");
        }
        return check;               
    }                 

    var name = prompt("What is your name?");
    var weight = prompt("what is your weight?");

    document.getElementById("print").innerHTML = check(name, weight);
</script>

为什么不生成javascript函数的输出？

4 个答案: