lovecoding
/
W0407


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #box {
            width: 200px;
            height: 200px;
            color: #fff;
            font-size: 30px;
            background: #00f;
        }
    </style>
</head>

<body>
    <div id="box"></div>
    <script>
        var box = document.getElementById("box");
        let x = 0;

        /**
         * 节流
         *  规定的时间内 只能触发一次函数 在规定时间内再次触发函数 无效 必须等函数完成后才能在执行
         *  防止频繁执行代码 减少性能消耗
         * 
        */
        function fn1() {
            box.innerText = x++;
        }
        function throttle(fn, delay) {
            // 闭包
            var timer = null;
            return function () {
                if (!timer) {
                    timer = setTimeout(function () {
                        fn();
                        timer = null;
                    }, delay)
                }
            }
        }

        //   box.onclick = function() {
        //     fn1()
        //   }
        box.addEventListener("click", throttle(fn1, 3000))
    </script>
</body>

</html>