tost提示

 <style>
        *{
            padding: 0;
            margin: 0;
        }
        .yg-toast{
            position: fixed;
            background: rgba(0,0,0,.7);
            border-radius: 4px;
            top: 50%;
            left: 50%;
            transform: translate(-50%,-50%);
            max-width: 60%;
            text-align: center;
            transition: all .1s;
        }
        .yg-toast-text{
            color: #fff;
            padding: 4px 10px;
            padding-bottom: 6px;
        }
    </style>

//tost提示
    (function(window , undefined ){
        var Ygtoast = function(){ //构造函数大驼峰命名法
        };
        Ygtoast.prototype={  //prototype 属性使您有能力向对象添加属性和方法。
            create: function(str,duration) {
                let self = this;
                var toastHtml = '';
                var toastText = '<div class="yg-toast-text">'+str+'</div>';
                toastHtml = '<div class="yg-toast">'+toastText+'</div>';
                if(document.querySelector(".yg-toast"))return;    //当还没hide时禁止重复点击
                document.body.insertAdjacentHTML('beforeend', toastHtml);
                duration == null ? duration=2000 : '';  //如果toast没有加上时间，默认2000毫秒；
                self.show();
                setTimeout(function(){
                    self.hide();
                }, duration);
            },
            show:function(){
                let self = this;
                document.querySelector(".yg-toast").style.display = "block";
                document.querySelector(".yg-toast").style.marginTop =  "-"+Math.round(document.querySelector(".yg-toast").offsetHeight/2)+"px";
                if(document.querySelector(".yg-toast"))return;
            },
            hide:function(){
                var self = this;
                if(document.querySelector(".yg-toast")){
                    document.querySelector(".yg-toast").parentNode.removeChild(document.querySelector(".yg-toast"));
                }
            },
            toast:function(str,duration){
                var self = this;
                return self.create(str,duration);
            }
        };
        window.Ygtoast = Ygtoast;
    }(window));
    // 调用
   var yg = new Ygtoast();
   yg.toast("你说神马",1500);