javascript – 随机将类添加到两个div

我有一个两列红色/黑色网格50/50％和高度100％,并有一个脚本,可以在加载页面时随机化两者的外观,所以左或右.我将两列网格后面的代码从相对位置和右边的浮动位置改为固定的绝对位置.这必须做,因为在移动时这种滚动行为这种方式更好.

下面的代码在使用浮动时工作正常,它会向左或向右添加一个类,使红色边选择一个随机边,黑色自动跟随,因为它是相对于彼此的.使用绝对和固定位置更改,它必须向左侧或右侧添加一个类才能工作.有人知道如何添加这个,所以当剩下红色时,黑色是正确的,反之亦然.

// Random red & black //

window.addEventListener('load',function() {
  // This is a ternary operator,which is just a shorthand way to 
  // do an if/else statement. This basically says,if the random number
  // is less than .5,assign "left" to the scenario variable.
  // if it is greater (or equal to),assign "right" to the variable. 
  var scenario = Math.random() < .5 ? "left" : "right";

  document.querySelector(".red",).classList.add("" + scenario);
});

.left {
  left: 0;
}

.right {
  right: 0;
}

.red,.black {
  width: 50%;
  height: 100%;
}

.black {
  position: absolute;
  background-color: black;
}

.red {
  position: fixed;
  background-color: red;
}

<div class="red"></div>
<div class="black"></div>

解决方法

这是你的解决方案：

// Random red & black //

window.addEventListener('load',function() {
// This is a ternary operator,which is just a shorthand way to 
// do an if/else statement. This basically says,if the random number
// is less than .5,assign "left" to the scenario variable.
// if it is greater (or equal to),assign "right" to the variable.
var scenario = Math.random() < .5 ? "left" : "right";
var scenario2 = scenario == "left" ? "right" : "left";

document.querySelector(".red",).classList.add("" + scenario);
document.querySelector(".black",).classList.add("" + scenario2);

});

.left { left: 0;}
.right { right: 0;}

.red,.black {
  width: 50%;
  height: 100%;
}

.black {
  position: absolute;
  background-color: black;
}

.red {
  position: fixed;
  background-color: red;
}

<div class="red"></div>
<div class="black"></div>