<html> <head> <link rel="stylesheet" href="./jquery-ui-1.12.1/jquery-ui.min.css" /> <title>实现div拖拽时出现辅助线，以方便和其它div很容易的对齐</title> </head> <body> <div class="container"> <!-- 需要拖动的div --> <div class="draggable">第一个div</div> <div class="draggable">第二个div</div> <div class="draggable">第三个div</div> <div class="draggable">第四个div</div> <div class="draggable">第五个div</div> <div class="draggable">第六个div</div> <!-- 拖动辅助线 --> <div id="guide-h" class="guide"></div> <div id="guide-v" class="guide"></div> </div> <script src="./jquery-ui-1.12.1/external/jquery/jquery.js"></script> <script src="./jquery-ui-1.12.1/jquery-ui.min.js"></script> <script type="text/javascript"> var MIN_DISTANCE = 8 //捕获的最小距离 var guides = [] // 指标拖动辅助标线 var innerOffsetX, innerOffsetY $('.draggable').draggable({ start: function(event, ui) { guides = $.map($('.draggable').not(this), computeGuidesForElement) // offsetX、offsetY：源元素（srcElement）的X, Y坐标 innerOffsetX = event.offsetX innerOffsetY = event.offsetY }, drag: function(event, ui) { // 迭代所有的guids，记住最近的h和v guids var guideV, guideH, distV = MIN_DISTANCE + 1, distH = MIN_DISTANCE + 1, offsetV, offsetH var chosenGuides = { top: { dist: MIN_DISTANCE + 1 }, left: { dist: MIN_DISTANCE + 1 } } var $t = $(this) // pageX、pageY：文档坐标x、y var pos = { // top: event.pageY - innerOffsetY, // left: event.pageX - innerOffsetX top: event.clientY - innerOffsetY, left: event.clientX - innerOffsetX } // outerHeight、outerWidth：整个浏览器的高度、宽度 var w = $t.outerWidth() - 1 var h = $t.outerHeight() - 1 var elemGuides = computeGuidesForElement(null, pos, w, h) $.each(guides, function(i, guide) { $.each(elemGuides, function(i, elemGuide) { if (guide.type == elemGuide.type) { var prop = guide.type == 'h' ? 'top' : 'left' var d = Math.abs(elemGuide[prop] - guide[prop]) if (d < chosenGuides[prop].dist) { chosenGuides[prop].dist = d chosenGuides[prop].offset = elemGuide[prop] - pos[prop] chosenGuides[prop].guide = guide } } }) }) if (chosenGuides.top.dist <= MIN_DISTANCE) { $('#guide-h') .css('top', chosenGuides.top.guide.top) .show() ui.position.top = chosenGuides.top.guide.top - chosenGuides.top.offset } else { $('#guide-h').hide() ui.position.top = pos.top } if (chosenGuides.left.dist <= MIN_DISTANCE) { $('#guide-v') .css('left', chosenGuides.left.guide.left) .show() ui.position.left = chosenGuides.left.guide.left - chosenGuides.left.offset } else { $('#guide-v').hide() ui.position.left = pos.left } }, stop: function(event, ui) { $('#guide-v, #guide-h').hide() } }) /** * 计算 DOM 元素辅助线 * @param {String, Object} elem DOM 选择器 * @param {Object} pos 位置坐标 * @param {Number} w 宽度 * @param {Number} h 高度 * @returns {Array} 辅助线对象数组 */ function computeGuidesForElement(elem, pos, w, h) { if (elem != null) { var $t = $(elem) // offset - 返回当前元素的偏移量 pos = $t.offset() w = $t.outerWidth() - 1 h = $t.outerHeight() - 1 } // type，方向类型，h - 垂直方向；v - 水平方向。 const guids = [ // 垂直方向 - 顶端对齐线 { type: 'h', left: pos.left, top: pos.top }, // 垂直方向 - 中心对齐线 { type: 'h', left: pos.left, top: pos.top + h / 2 }, // 垂直方向 - 中心对齐线 { type: 'h', left: pos.left, top: pos.top + h }, // 水平方向 - 左侧对齐线 { type: 'v', left: pos.left, top: pos.top }, // 水平方向 - 中心对齐线 { type: 'v', left: pos.left + w / 2, top: pos.top }, // 水平方向 - 左侧对齐线 { type: 'v', left: pos.left + w, top: pos.top } ] return guids } </script> <style type="text/css"> * { padding: 0px; margin: 0px; } body { height: 100%; overflow-x: hidden; overflow-y: hidden; } .container { width: 100vw; min-height: 90vh; margin: 0px auto; position: relative; overflow: auto; border-bottom: 1px gray solid; } .draggable { width: 200px; height: 100px; border: 1px solid #ccc; display: inline-block; cursor: move; position: absolute !important; top: 0px; left: 0px; } .guide { display: none; position: absolute; left: 0; top: 0; } #guide-h { border-top: 1px red solid; width: 100%; } #guide-v { border-left: 1px red solid; height: 100%; } </style> </body> </html>