Web page change theme and drawing JS code implementation

HTML code implementation:

<! DOCTYPE html>CSS code implementation: WUPIFU.CSS 
 #btn1 {width:100px;    height:50px;    Background-color:aqua;    border-radius:25px;    Position:absolute; left:37px;    } #btn2 {width:100px;    height:50px;    Background-color:blueviolet;    border-radius:25px;    Position:absolute; left:150px;    } #btn3 {width:100px;    height:50px;    Background-color:gold;    border-radius:25px;    Position:absolute; left:260px;    } #btn4 {width:100px;    height:50px;    Background-color:deeppink;    border-radius:25px;    Position:absolute; left:369px;    } #btn5 {width:100px;    height:50px;    Background-color:green;    border-radius:25px;    Position:absolute; left:477px;    } #btn6 {width:100px;    height:50px;    Background-color:blue;    border-radius:25px;    Position:absolute; left:585px;    } #btn7 {width:100px;    height:50px;    Background-color:darksalmon;    border-radius:25px;    Position:absolute; left:693px; }
Zuotu.css
#tb {    background-color:antiquewhite;    border:1px solid black;    Border-collapse:collapse;    margin:100px Auto;} #tb td {    width:500px;    height:400px;    border:1px solid black;    Vertical-align:center;    Text-align:center;} #setbtn {    width:100px;    height:40px;    Color:white;    Background-color: #0181cc;} label {    font-size:20px;    font-family: ' Kaiti ';} input {    height:20px;    font-family: ' Kaiti ';} Select {    font-size:20px;    font-family: ' Kaiti ';}
　　
Web page change theme and drawing JS code implementation