1.封装方法: var textareaListener = { /*事件监听器兼容 * *attachEvent——兼容:IE7.IE8:不兼容firefox.chrome.IE9.IE10.IE11.safari.opera *addEventListener——兼容:firefox.chrome.IE.safari.opera:不兼容IE7.IE8 * */ compatibleEvtListener: function () { var observe; if (window.attac