js重写alert事件（避免alert弹框标题出现网址）
js代码：
window.alert=function(msg,callback){
vardiv=document.createElement("div");
div.innerHTML=""
+".nbaMask{position:fixed;z-index:1000;top:0;right:0;left:0;bottom:0;background:rgba(0,0,0,0.5);}"
+".nbaMaskTransparent{position:fixed;z-index:1000;top:0;right:0;left:0;bottom:0;}"
+".nbaDialog{position:fixed;z-index:5000;width:80%;max-width:300px;top:50%;left:50%;-webkit-transform:translate(-50%,-50%);transform:translate(-50%,-50%);background-color:#fff;text-align:center;border-radius:8px;overflow:hidden;opacity:1;color:white;}"
+".nbaDialog.nbaDialogHd{padding:.2rem.27rem.08rem.27rem;}"
+".nbaDialog.nbaDialogHd.nbaDialogTitle{font-size:17px;font-weight:400;}"
+".nbaDialog.nbaDialogBd{padding:0.27rem;font-size:15px;line-height:1.3;word-wrap:break-word;word-break:break-all;color:#000000;}"
+".nbaDialog.nbaDialogFt{position:relative;line-height:48px;font-size:17px;display:-webkit-box;display:-webkit-flex;display:flex;}"
+".nbaDialog.nbaDialogFt:after{content:\"\";position:absolute;left:0;top:0;right:0;height:1px;border-top:1pxsolid#e6e6e6;color:#e6e6e6;-webkit-transform-origin:00;transform-origin:00;-webkit-transform:scaleY(0.5);transform:scaleY(0.5);}"
+".nbaDialog.nbaDialogBtn{display:block;-webkit-box-flex:1;-webkit-flex:1;flex:1;color:#09BB07;text-decoration:none;-webkit-tap-highlight-color:transparent;position:relative;margin-bottom:0;}"
+".nbaDialog.nbaDialogBtn:after{content:\"\";position:absolute;left:0;top:0;width:1px;bottom:0;border-left:1pxsolid#e6e6e6;color:#e6e6e6;-webkit-transform-origin:00;transform-origin:00;-webkit-transform:scaleX(0.5);transform:scaleX(0.5);}"
+".nbaDialoga{text-decoration:none;-webkit-tap-highlight-color:transparent;}"
+""
+""
+"