Set default font-family according to operating system. 根据操作系统设置默认（中文）字体。

better-default-font-family.js

// @温柔的码农
// reset font-family according to OS
(function () {
	if (!navigator || !navigator.appVersion) {
		return;
	}
	if (navigator.appVersion.indexOf("Win") != -1) {
		// win 微软雅黑
		$('body').css('font-family', 'helvetica, arial, "Microsoft Yahei", simhei, sans-serif');
		return;
	}
	// mac 苹方, 苹果丽黑(冬青黑体)
	if (navigator.appVersion.indexOf("Mac") != -1) {
		$('body').css('font-family', '"San Francisco", helvetica, arial, "Pingfang SC", "Hiragino Sans GB", simhei, sans-serif');
		return;
	}
	// ubuntu 文泉驿微米黑
	if (navigator.appVersion.indexOf("X11") != -1 || navigator.appVersion.indexOf("Linux") != -1) {
		$('body').css('font-family', 'helvetica, arial, "WenQuanYi Micro Hei", simhei, sans-serif');
	}
})();