前端学习之DOM编程案例：抽奖案例

代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>抽奖案例</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
    </style>
</head>
<body>
    <div id="container">
    </div>
    <script>
        let div0 = document.querySelector('#container')
        //最外边的大盒子
        div0.style.width = 800 +'px'
        div0.style.height = 900 +'px'
        div0.style.border = '1px dashed red'        
        div0.style.margin = 'auto'
        div0.style.textAlign = 'center'
        //抽奖显示的圆
        let cirle =  document.createElement('div')
        cirle.style.borderRadius = '50%'
        // cirle['borderRadius'] = '50%'
        // cirle['backgroundColor'] = 'red'
        cirle.style.backgroundColor = 'red'
        cirle.style.width = 300 + 'px'
        cirle.style.height = 300 + 'px'
        cirle.style.margin = 'auto'
        cirle.textContent = '宝马五元代金卷'
        cirle.style.fontSize = '30px'
        cirle.style.color = 'white'
        cirle.style.marginTop = '80px'
        cirle.style.lineHeight = '300px'
        cirle.style.textAlign='center'
        div0.appendChild(cirle)
        //抽奖按钮
        let button1 = document.createElement('button')
        button1.style.width=300+'px'
        button1.style.height=40+'px'
        button1.textContent = '开始抽奖'
        button1.style.margin='auto'
        button1.style.marginTop = 40+'px'
        let btn_status = '开始抽奖'
        //奖品
        let arr = ['宝马五元代金卷','兰博基尼五元代金卷','法拉利五元代金卷','iphone五元代金卷']    
        //抽奖逻辑
        button1.onclick = function(){
            if (btn_status == '开始抽奖'){
            id = setInterval(start,10)
            }
            else{
                btn_status = '开始抽奖'
                button1.textContent = btn_status
                clearInterval(id)
            } 
        }
       
        div0.appendChild(button1)
        function start(){
            
                index = Math.ceil(Math.random()*4)
                cirle.textContent = arr[index]
                btn_status = '停止抽奖'
                button1.textContent = btn_status
            
            
        }

    </script>
</body>
</html>