Unsafe common js writing methods_javascript skills

Copy code The code is as follows:

document.write('');

Until the anti-virus software prompts that there is malicious The code found out that this is also unsafe, sweat...

Then I had to change it to this:

Copy code The code is as follows:

(function() {
var s = document.createElement('script');
s.type = 'text/javascript';
s.src = 'http://a.com.cn/b.js';
document.getElementsByTagName('head')[0].appendChild(s);
})();