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javascript implements random generation of DIV background colors

  • 2021-06-29 06:20:21
  • OfStack

Random colors come in two formats:
Effect Preview: http://wjf444128852.github.io/DEMOLIST/JS/test/index.html
1. rgb (xxx, xxx, xxx)
2. #xxxxxx
Here are two random methods
Idea: How to make x random,
1. xxx in is a random integer between 0 and 255. Use Math.random()*255 to get a random number between 0 and 255.
Then Math.floor() preserves the one before the decimal point
2. The x in the is a random combination of six in 0123456789 abxdef.
Arrays or strings can be used here. Arrays are used here, as long as they are taken six times from the array and each time the array subscript is a random integer between 0 and 16.
Note (Although the change in Fa 2 is #XXXX, at this point the browser looks at the background-color attribute value of the DOM element in rgb format, the assignment in JS is in #xxx format.)
The code is as follows:
HTML 


<body>
  <div class="main">
    <p><a href="javascript:;" id="btn-one">RandomColor-rgb</a></p>
    <ul>
      <li><div class="bg_color"></div></li>
      <li><div class="bg_color"></div></li>
      <li><div class="bg_color"></div></li>
      <li><div class="bg_color"></div></li>
    </ul>
  </div>
  <div class="main">
    <p><a href="javascript:;" id="btn-two">RandomColor-#XXXXXX</a></p>
    <ul>
      <li><div class="bg_two"></div></li>
      <li><div class="bg_two"></div></li>
      <li><div class="bg_two"></div></li>
      <li><div class="bg_two"></div></li>
    </ul>
  </div>
</body>

CSS 


*{
      box-sizing: border-box;
      list-style: none;
      border: none;
      padding: 0;
      margin: 0;
    }
    p{
      text-align: center;
      margin: 20px;
    }
    p a{
      font-size: 20px;
      font-weight: 300;
      color: #e4393c;
      text-decoration: none;
      padding: 6px 10px;
      border: 1px solid currentColor;
    }
    .bg_color,.bg_two{
      width: 100px;
      height: 100px;
      border: 1px solid #aa00aa;
    }
    .main,.main ul{
      overflow: hidden;
    }
    .main{
      width: 400px;
      margin:30px auto;
    }
    .main ul li{
      float: left;
    }

JS 


<script>
  (function(){
    //1 Functions of random colors -rgb
    function getRandomColor(){
      var rgb='rgb('+Math.floor(Math.random()*255)+','   

      +Math.floor(Math.random()*255)+','  

      +Math.floor(Math.random()*255)+')';
      console.log(rgb);
      return rgb;
    }
//   Get Button 
    var btn_one=document.querySelector("#btn-one");
    var Divs=document.querySelectorAll(".bg_color");
    btn_one.onclick=function(){
      for(var i=0;i<Divs.length;i++){
        Divs[i].style.backgroundColor=getRandomColor();
      }
    };
    //2 , random colors #XXXXXX
    var btn_two=document.querySelector("#btn-two");
    var divsTwo=document.querySelectorAll(".bg_two");
    var chars = ['0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'];
    function generateMixed(n) {
      var res = "#";
      var id;
      for(var i = 0; i < n ; i ++) {
        id= Math.floor(Math.random()*16);
        res += chars[id];
      }
      console.log(id,res);
      return res;
    }
    btn_two.onclick=function(){
      for(var i=0;i<divsTwo.length;i++){
        divsTwo[i].style.backgroundColor=generateMixed(6);
      }
    };
  })()
</script>
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