为什么 javascript if/else 语句不起作用

Question

我试着写了一小段代码，但是没有用。

它应该如何工作：有一个 if 函数语句，它在 iPhone/iPod 和 else

之间过滤

问题是它不起作用。

$(function() {
if((navigator.userAgent.match(/iPhone/i)) || (navigator.userAgent.match(/iPod/i))) {
        function openNav() {
        document.getElementById("mySidenav").style.width = "360px";
    }
        function closeNav() {
        document.getElementById("mySidenav").style.width = "0";
    }
} else {
    function openNav() {
      document.getElementById("mySidenav").style.width = "360px";
      document.getElementById("main").style.marginLeft = "360px";
    }
    function closeNav() {
      document.getElementById("mySidenav").style.width = "0";
      document.getElementById("main").style.marginLeft= "0";
      document.body.style.backgroundColor = "white";
    }
  }
    
});

坦克你们！

Answer 1

您需要做的就是在别处声明函数，然后在 if/else 语句中调用它们。

1-声明所有函数：

function openNav() {
    document.getElementById("mySidenav").style.width = "360px";
}
function closeNav() {
    document.getElementById("mySidenav").style.width = "0";
}
function openNavWithMargin() {
    document.getElementById("mySidenav").style.width = "360px";
    document.getElementById("main").style.marginLeft = "360px";
}
function closeNavWithMargin() {
    document.getElementById("mySidenav").style.width = "0";
    document.getElementById("main").style.marginLeft= "0";
    document.body.style.backgroundColor = "white";
}

2-在if/else语句中调用它们：

$(function() {
if((navigator.userAgent.match(/iPhone/i)) || (navigator.userAgent.match(/iPod/i))) {
    openNav();
    closeNav();
} else {
    openNavWithMargin();
    closeNavWithMargin();
  }
    
});

Answer 2

您需要根据自己的需要编写如下代码。

 function openNav() {
    document.getElementById("main").style.marginLeft = "360px"; //common code

    if(!((navigator.userAgent.match(/iPhone/i)) || (navigator.userAgent.match(/iPod/i)))) {
        document.getElementById("main").style.marginLeft = "360px";
    }
  }

  function closeNav() {
    document.getElementById("mySidenav").style.width = "0"; //common code
    if(!((navigator.userAgent.match(/iPhone/i)) || (navigator.userAgent.match(/iPod/i)))) {
        document.getElementById("main").style.marginLeft= "0";
        document.body.style.backgroundColor = "white";
    }   
  }
  

$(function() {
   // Call your function from here as per the requirement.
    openNav();
    closeNav();
});

为什么 javascript if/else 语句不起作用

Why does the javascript if/else statement not working

javascript

user-agent