該插件最初的想法來自網上的一篇文章，直達鏈接：https://www.cnblogs.com/libin-1/p/6220056.html
筆者因為業務需要尋找到這個插件，然后拿來用之，發現各種不方便，然后便開始了改造之路。
上代碼：
1 <script> 2 function dragSlide(id) { 3 this.minDiv =document.getElementById(id); //小方塊 4 5 this.width = parseInt(window.getComputedStyle(this.minDiv, null).width); //小方塊的寬度 6 7 this.lineDiv = this.minDiv.parentNode; //長線條 8 9 //滑動的數值呈現 10 this.vals = this.minDiv.children[0]; 11 12 var that=this; 13 var move = function(e) { 14 var x = e.touches[0].pageX; 15 var lineDiv_left = that.getPosition(that.lineDiv).left; //長線條的橫坐標 16 var minDiv_left = x - lineDiv_left; //小方塊相對於父元素（長線條）的left值 17 if (minDiv_left >= that.lineDiv.offsetWidth - that.width) { 18 minDiv_left = that.lineDiv.offsetWidth - that.width; 19 } 20 if (minDiv_left <0 ) { 21 minDiv_left = 0; 22 } 23 //設置拖動后小方塊的left值 24 that.minDiv.style.left = minDiv_left + "px"; 25 //percent百分比改為如下所示,解決開始和最后滑動的體驗不好問題 26 var percent = (minDiv_left / (that.lineDiv.offsetWidth - that.width)) * 100; 27 if (percent > 0 && percent < 0.5) { 28 percent = Math.ceil(percent); 29 } else { 30 percent = Math.floor(percent); 31 } 32 that.vals.innerText = percent; 33 } 34 //獲取元素的絕對位置,工具函數 35 this.getPosition = function(node) { 36 var left = node.offsetLeft; //獲取元素相對於其父元素的left值var left 37 var top = node.offsetTop; 38 current = node.offsetParent; // 取得元素的offsetParent 39 // 一直循環直到根元素 40 41 while (current != null) { 42 left += current.offsetLeft; 43 top += current.offsetTop; 44 current = current.offsetParent; 45 } 46 return { 47 "left": left, 48 "top": top 49 }; 50 } 51 this.minDiv.addEventListener("touchmove", move); 52 } 53 var drag0 = new dragSlide("minDiv"); 54 var drag1 = new dragSlide("minDiv1"); 55 //取消移動端手勢長按彈出提示框的操作 56 document.addEventListener('contextmenu', function(e) { 57 e.preventDefault(); 58 }); 59 60 </script>
html和css部分沒有改動，而js改動還是很大的，比較原來作者的文章，改動點如下
1）整體上，原來不是插件，改造之后成為一個可以復用的插件，雖然簡單了點
2）只是將其改造為適用於移動端的插件
3）通過對開始滑動和結束滑動比例的處理，優化了開始滑動和結束滑動的體驗
4）移動端加了防止長按彈出提示框的代碼
5）小滑塊的寬度改為動態
改造之后的整體案例，需要指出：筆者主要用在微信端，至於其他瀏覽器滑塊的體驗不是很好，還有滑塊滑動體驗跟小塊的尺寸有直接關系。
1 <!DOCTYPE html> 2 <html lang="zh-cn"> 3 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 6 <meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no" /> 7 <title>鼠標拖動小方塊</title> 8 <style type="text/css"> 9 .lineDiv { 10 position: relative; 11 height: 5px; 12 background: red; 13 width: 300px; 14 margin: 50px auto; 15 } 16 17 .lineDiv .minDiv { 18 position: absolute; 19 top: -12.5px; 20 left: 0; 21 width: 30px; 22 height: 30px; 23 background: green; 24 cursor: pointer 25 } 26 27 .lineDiv .minDiv .vals { 28 position: absolute; 29 font-size: 20px; 30 top: -45px; 31 left: -2.5px; 32 width: 35px; 33 height: 35px; 34 line-height: 35px; 35 text-align: center; 36 background: blue; 37 } 38 39 .lineDiv .minDiv .vals:after { 40 content: ""; 41 width: 0px; 42 height: 0px; 43 border-top: 6px solid blue; 44 border-left: 6px solid transparent; 45 border-right: 6px solid transparent; 46 border-bottom: 6px solid transparent; 47 display: block; 48 margin-left: 11px; 49 } 50 51 * { 52 -webkit-user-select: none; 53 -moz-user-select: none; 54 -ms-user-select: none; 55 user-select: none; 56 } 57 </style> 58 </head> 59 60 <body> 61 <center> 62 <h3>用鼠標拖動小方塊<span id="msg">0</span>%</h3> 63 </center> 64 <div id="lineDiv" class="lineDiv"> 65 <div id="minDiv" class="minDiv"> 66 <div id="vals" class="vals">0</div> 67 </div> 68 </div> 69 <div style="height: 20px;"></div> 70 <div id="lineDiv" class="lineDiv"> 71 <div id="minDiv1" class="minDiv"> 72 <div id="vals" class="vals">0</div> 73 </div> 74 </div> 75 <script> 76 //避免默認事件 2018.7.10 更新 優化uc瀏覽器左右滑動時候頁面被拖動 77 document.addEventListener('touchmove', function(e) { 78 e.preventDefault(); 79 }, { passive: false }); 80 81 function dragSlide(id) { 82 this.minDiv = document.getElementById(id); //小方塊 83 84 this.width = parseInt(window.getComputedStyle(this.minDiv, null).width); //小方塊的寬度 85 86 this.lineDiv = this.minDiv.parentNode; //長線條 87 88 //滑動的數值呈現 89 this.vals = this.minDiv.children[0]; 90 91 var that = this; 92 var lastX = null; //判斷鼠標移動方向，解決向左側滑動時候的bug 93 var move = function(e) { 94 var x = e.touches[0].pageX, 95 direction = ''; 96 if (lastX == null) { 97 lastX = x; 98 return; 99 } 100 if (x > lastX) { 101 direction = 'right'; 102 } else if (x < lastX) { 103 direction = 'left'; 104 } else { 105 direction = ''; 106 } 107 108 var lineDiv_left = that.getPosition(that.lineDiv).left; //長線條的橫坐標 109 var minDiv_left = x - lineDiv_left; //小方塊相對於父元素（長線條）的left值 110 if (minDiv_left >= that.lineDiv.offsetWidth - that.width) { 111 minDiv_left = that.lineDiv.offsetWidth - that.width; 112 } 113 if (minDiv_left < 0) { 114 minDiv_left = 0; 115 } 116 //設置拖動后小方塊的left值 117 that.minDiv.style.left = minDiv_left + "px"; 118 //percent百分比改為如下所示,解決開始和最后滑動的體驗不好問題 119 var percent = (minDiv_left / (that.lineDiv.offsetWidth - that.width)) * 100; 120 if (percent < 0.5 && direction == 'right') { 121 percent = Math.ceil(percent); 122 } else if (percent > 0.5 && direction == 'right') { 123 percent = Math.floor(percent); 124 } else { 125 percent = Math.ceil(percent); 126 } 127 that.vals.innerText = percent; 128 } 129 //獲取元素的絕對位置,工具函數 130 this.getPosition = function(node) { 131 var left = node.offsetLeft; //獲取元素相對於其父元素的left值var left 132 var top = node.offsetTop; 133 current = node.offsetParent; // 取得元素的offsetParent 134 // 一直循環直到根元素 135 136 while (current != null) { 137 left += current.offsetLeft; 138 top += current.offsetTop; 139 current = current.offsetParent; 140 } 141 return { 142 "left": left, 143 "top": top 144 }; 145 } 146 this.minDiv.addEventListener("touchmove", move); 147 } 148 var drag0 = new dragSlide("minDiv"); 149 var drag1 = new dragSlide("minDiv1"); 150 //取消移動端手勢長按彈出提示框的操作 151 document.addEventListener('contextmenu', function(e) { 152 e.preventDefault(); 153 }); 154 </script> 155 </body> 156 157 </html>
本文結束，2018年6月19日，修改bug
本文結束，2018年7月10日，優化