function escape(s) { return '<script>console.log("' + s.toUpperCase() + '")</script>'; }
尝试：
输入的 alert 进行了大写转换，ALERT(1)无法执行。
网上有一种jsfuck的混肴编码（https://en.wikipedia.org/wiki/JSFuck）。将alert(1)编码为下面的可执行内容（http://utf-8.jp/public/jsfuck.html）：
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也可以将 alert 进行html编码。