利用JavaScript实现一个拖拽选择和删除功能？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。
结果如下：
代码如下：
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>js置顶动画</title>
<style>
*{margin:0;padding:0;user-select:none;}
.move-box {height:100px;width:100px;line-height:100px;text-align:center;font-size:14px;background:#ccc;margin:0 auto;position:relative;transition:all .1s;}
.drag-box{width:1000px;margin:100px auto;border:1px dashed #ccc;font-size:0;background:url('./img/bg1.png') no-repeat center;background-size:80px;}
.drag-box::after{content:'';display:block;clear:both;} /***清浮动***/
.drag-box .label{height:100px;width:0;color:#fff;line-height:0;text-align:center;font-size:14px;display:inline-block;background:blue;}
.drag-box .close-btn{padding:2px;margin-left:10px;background:#eee;}
</style>
</head>
<body>
<div class="move-box">拖动元素</div>
<div class="drag-box">
<div class="label"></div>
</div>
</body>
<script>
(function(){
let boxId = 0;
let startX = null;
let startY = null;
let mouseX = null;
let mouseY = null;
let mBox = null;
function $$(str) {return document.querySelectorAll(str);}
// 计算鼠标是否在需要放置的框内
function computInEle(ele, x, y){
let left = ele.getBoundingClientRect().left;
let top = ele.getBoundingClientRect().top;
let width = ele.getBoundingClientRect().width;
let height = ele.getBoundingClientRect().height;
let xFlag = ( x > left && x < (left + width));
let yFlag = ( y > top && y < (top + height));
if (xFlag && yFlag) {
return true;
} else {
return false;
}
}
// 删除元素
$$('.drag-box')[0].onclick = function(e){
console.log(e);
if (e.srcElement.className == 'close-btn') {
this.removeChild(e.srcElement.parentNode);
setTimeout(() => {
alert('删除成功！');
}, 0);
}
}
// 鼠标按下复制一个元素
$$('.move-box')[0].onmousedown = function(e){
mouseX = e.pageX;
mouseY = e.pageY;
startX = this.getBoundingClientRect().left;
startY = this.getBoundingClientRect().top;
console.log(this.getBoundingClientRect());
// 复制一个元素追加到body模拟跟随鼠标移动效果
mBox = this.cloneNode(true);
mBox.style.position = 'fixed';
mBox.style.zIndex = '9999';
mBox.style.opacity = '.75';
mBox.style.left = startX + 'px';
mBox.style.top = startY + 'px';
mBox.id = 'moveBox' + (boxId++);
document.body.appendChild(mBox);
document.onmousemove = function(e){
mBox.style.left = startX + (e.pageX - mouseX) + 'px';
mBox.style.top = startY + (e.pageY - mouseY) + 'px';
};
};
// 鼠标按下放开事件
document.onmouseup = function(e){
let x = e.pageX;
let y = e.pageY;
let ele = $$('.drag-box')[0];
console.log(computInEle(ele, x, y));
if (mBox) {
// 松开鼠标时鼠标在拖拽框内，则将复制的元素追加到拖拽框内
if (computInEle(ele, x, y)) {
mBox.style.position = 'static';
mBox.style.display = 'block';
mBox.style.float = 'left';
mBox.style.margin = 'auto';
mBox.style.opacity = '1';
mBox.innerText = mBox.innerText +(boxId - 1);
let close = document.createElement('span');
close.className = 'close-btn';
close.innerText = '×';
close.title = '删除元素';
mBox.appendChild(close);
ele.appendChild(mBox);
mBox.onmousedown = null;
} else {
// 松开鼠标时鼠标不在拖拽框内，移除复制的元素
mBox.style.left = startX + 'px';
mBox.style.top = startY + 'px';
document.body.removeChild(document.body.lastElementChild);
}
startX = null;
startY = null;
mouseX = null;
mouseY = null;
mBox = null;
document.onmousemove = null;
}
};
})();
</script>
</html>看完上述内容，你们掌握利用JavaScript实现一个拖拽选择和删除功能的方法了吗？如果还想学到更多技能或想了解更多相关内容，欢迎关注亿速云行业资讯频道，感谢各位的阅读！
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