<html>
<head>
<title>框选功能</title>
<style>
body {
margin: 0;
padding: 0;
}
#index_wrap {
width: 100%; /* 演示宽高与位置 */
height:100vh;
border: 1px solid #eee;
}
.wrap_item {
display: inline-block;
width: 100px;
height: 100px;
margin: 24px;
background-color: #0082CC;
}
</style>
</head>
<body>
<div id="index_wrap">
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
<div class="wrap_item"></div>
</div>
</body>
</html>
<script>
(function () {
var mouseStopId;
var mouseOn = false;
var startX = 0;
var startY = 0;
// 获取容器元素
var index_wrap = document.getElementById('index_wrap');
index_wrap.onmousedown = function (e) {
clearEventBubble(e);
if (e.buttons !== 1 || e.which !== 1) return;
mouseStopId = setTimeout(function () {
mouseOn = true;
// 调整坐标原点为容器左上角
startX = e.clientX - index_wrap.offsetLeft + index_wrap.scrollLeft;
startY = e.clientY - index_wrap.offsetTop + index_wrap.scrollTop;
var selDiv = document.createElement('div');
selDiv.style.cssText = 'position:absolute;width:0;height:0;margin:0;padding:0;border:1px dashed #eee;background-color:#aaa;z-index:1000;opacity:0.6;display:none;';
selDiv.id = 'selectDiv';
// 添加框选元素到容器内
document.getElementById('index_wrap').appendChild(selDiv);
selDiv.style.left = startX + 'px';
selDiv.style.top = startY + 'px';
}, 20);
document.onmousemove = function (e) {
if (!mouseOn) return;
clearEventBubble(e);
var index_wrap = document.getElementById('index_wrap');
var _x = e.clientX - index_wrap.offsetLeft + index_wrap.scrollLeft;
var _y = e.clientY - index_wrap.offsetTop + index_wrap.scrollTop;
var _H = index_wrap.offsetWidth
// 鼠标移动超出容器内部，进行相应的处理
// 向右拖拽
if (e.clientX > index_wrap.offsetLeft + index_wrap.offsetWidth) {
let maxLeft = index_wrap.scrollWidth - index_wrap.offsetWidth
let step = index_wrap.scrollLeft + 20
if (step >= maxLeft) {
index_wrap.scrollLeft = maxLeft
} else {
index_wrap.scrollLeft = step
}
}
// 向左拖拽
if (e.clientX < index_wrap.offsetLeft) {
let minLeft = 0
let step = index_wrap.scrollLeft - 20
if (step <= minLeft) {
index_wrap.scrollLeft = minLeft
} else {
index_wrap.scrollLeft = step
}
}
var selDiv = document.getElementById('selectDiv');
selDiv.style.display = 'block';
selDiv.style.left = Math.min(_x, startX) + 'px';
selDiv.style.top = Math.min(_y, startY) + 'px';
if ((Math.min(_x, startX) + Math.abs(_x - startX)) <= index_wrap.scrollWidth) {
selDiv.style.width = Math.abs(_x - startX) + 'px';
}
selDiv.style.height = Math.abs(_y - startY) + 'px';
};
document.onmouseup = function (e) {
if (!mouseOn) return;
clearEventBubble(e);
var selDiv = document.getElementById('selectDiv');
var wrap_items = document.getElementsByClassName('wrap_item');
var selectedEls = [];
var l = selDiv.offsetLeft;
var t = selDiv.offsetTop;
var w = selDiv.offsetWidth;
var h = selDiv.offsetHeight;
for (var i = 0; i < wrap_items.length; i++) {
var sl = wrap_items[i].offsetWidth + wrap_items[i].offsetLeft;
var st = wrap_items[i].offsetHeight + wrap_items[i].offsetTop;
if (sl > l && st > t && wrap_items[i].offsetLeft < l + w && wrap_items[i].offsetTop < t + h) {
wrap_items[i].style.background = 'red'
selectedEls.push(wrap_items[i]);
}
}
console.log(selectedEls);
selDiv.style.display = 'none';
mouseOn = false;
};
}
function clearEventBubble (e) {
if (e.stopPropagation) e.stopPropagation();
else e.cancelBubble = true;
if (e.preventDefault) e.preventDefault();
else e.returnValue = false;
}
})();
</script>
