SOURCE

window.onload = function(){
    let d1 = new Drag();
    d1.init('div1');
    let d2 = new Drag();
    d2.init('div2');
    let d3 = new Drag();
    d3.init('div3');
    let d4 = new Drag();
    d4.init('div4');
}

// Drag构造函数
function Drag(){
    this.obj = null;
    this.disX = 0;
    this.disY = 0;
    this.settings = {

    }
}

Drag.prototype.init = function(id,opt){
    this.obj = document.getElementById(id);
    var _this = this;
    this.obj.onmousedown = function(ev){
        var ev = ev || window.event;
        _this.toDown(ev);
        document.onmousemove = function(ev){
            var ev = ev || window.event;
            _this.toMove(ev);
        }
        document.onmouseup = function(){
            _this.toUp();
        }
    }   
}

// 拖拽三大事件
// 1.鼠标按下
Drag.prototype.toDown = function(ev){
    this.disX = ev.clientX - this.obj.offsetLeft;
    this.disY = ev.clientY - this.obj.offsetTop;
    // 元素被选中的时候的样式的添加
    this.obj.classList.add('checkdiv');
}

// 2.鼠标移动
Drag.prototype.toMove = function(ev){
    this.obj.style.left = ev.clientX - this.disX + 'px';
    this.obj.style.top = ev.clientY - this.disY + 'px';
}

// 3.鼠标抬起
Drag.prototype.toUp = function(){
    document.onmousedown = null;
    document.onmousemove = null;
    //元素选中结束时候的样式移除
    this.obj.classList.remove('checkdiv')
}



// 得到用户输入的宽数值
let wVal = 0;
let wbox = document.querySelector('#wVal');
wbox.onkeypress = function(ev){
    if(ev.which === 13){
        wVal = wbox.value;
        console.log(wVal);
    }
}

// 得到用户输入的高度数值
let hVal = 0;
let hbox = document.querySelector('#hVal');
hbox.onkeypress = function(ev){
    if(ev.which === 13){
        hVal = hbox.value;
        console.log(hVal);
    }
}

// 自定义颜色生成函数
function randomColor(){
    
}


// 元素生成事件按钮
let btn = document.querySelector('input[type="button"]');
// console.log(btn);

// 为按钮绑定事件
let i = 5;//新生成的按钮个数
btn.onclick = function(){
    let newDiv = [];
    newDiv[i] = document.createElement('div');
    newDiv[i].classList.add('div');
    newDiv[i].setAttribute('id','div' + i);
    newDiv[i].style.top = i * 50 + 'px';
    newDiv[i].style.width = wVal + 'px';
    newDiv[i].style.height = hVal + 'px';
    alert('事件触发了');
    document.body.appendChild(newDiv[i]);
    let d = [];
    d[i] = new Drag();
    d[i].init('div'+i);
    i++;
}

<!-- 拖拽组件开发 -->
<div id="div1"></div>
<div id="div2"></div>
<div id="div3"></div>
<div id="div4"></div>
<!-- 设置宽度 -->
<input type="text" placeholder="输入宽度,按下enter" id="wVal">
<!-- 设置高度 -->
<input type="text" placeholder="输入高度,按下enter" id="hVal">
<input type="button" value="CREATE" />

div{
    width: 100px;
    height: 80px;
    position: absolute;
    border: 1px solid #c994bd;
    cursor: move;
    border-radius: 10px 20px 10px 20px;
}
.checkdiv{
    border: 2px dashed red;
}
div:nth-child(1){
    left: 0px;
    background-color: pink;
}
div:nth-child(2){
    left: 110px;
    background-color: #5ac;
}
div:nth-child(3){
    left: 220px;
    background-color: #fa5;
}
div:nth-child(4){
    left: 330px;
    background-color: #1c5;
}
#hVal{
    position: absolute;
    left: 230px;
    bottom: 100px;
}
input[type="text"]{
    position: absolute;
    left: 50px;
    bottom: 100px;
    border: none;
    outline: none;
    width: 120px;
    height: 30px;
    border-radius: 0px 20px 20px 0px;
    border: 1px solid #c994bd;
    color: #5ac;
    transition: all .5s ease-in;
}
input[type="text"]:focus{
     width: 170px;
     border-color: rgb(13, 223, 223); 
     
}
input[type='button']{
    border: none;
    width: 100px;
    height: 40px;
    color: #c994bd;
    font-weight: 400;
    font-size: 18px;
    position: absolute;
    left: 50px;
    bottom: 50px;
    border: 1px solid #5ac;
    transition: all .3s linear;
}
input[type='button']:hover{
    border: 1px solid #c994bd;
    background-color: rgb(143, 224, 173);
    color: white;
    width: 120px;
    border-radius: 25px;
}