页面允许鼠标左键选中文本

user-select: text;
-moz-user-select: text;
-webkit-user-select: text;  /*webkit浏览器*/
-ms-user-select: text;   /*IE10*/
-khtml-user-select: text; /*早期浏览器*/
		user-select: text;
-moz-user-select: text;
-web