outiy5

<!-- https://stackoverflow.com/questions/5846137/script-inside-href-how-to -->
<a href="javascript:location='http://www.linkimprov.com/?ref='+encodeURI(location.href.match(/(?=https?:\/\/)?(?=www\.)?(.*)/)[1]).substring(7);"></a>

outiy5

// https://stackoverflow.com/questions/14213848/difference-between-and
// Both will match any sequence of one or more characters. The difference is that:
// .+ is greedy and consumes as many characters as it can.
// .+? is reluctant and consumes as few characters as it can.

var r0 = /\$[\s\S]+\$/g;
r0.exec('$s\nda$sd\n$') // match: $s\nda$sd\n$

var r1 = /\$[\s\S]+?\$/g;
r1.exec('$s\ndasd\n$') // match: $s\nda$

outiy5

// https://stackoverflow.com/questions/1979884/how-to-use-javascript-regex-over-multiple-lines
// use ? for non-greedy mode
// () use to capture
var regex = /\$([\s\S]+?)\$/g;
regex.exec('$s\ndasd\n$');

outiy5

// This one is wrong
<script type="text/javascript">document.write('<img src="http://chart.apis.google.com/chart?cht=tx&chl=' + escape('\\\\frac{1}{2}').replace(' ',"%20") + '" alt="">');</script>
// This one is right
// learn it from https://katex.org/docs/api.html
<script type="text/javascript">document.write('<img src="http://chart.apis.google.com/chart?cht=tx&chl=' + String.raw`$1`.replace(' ',"%20") + '" />');</script>

outiy5

//https://github.com/parcel-bundler/parcel/issues/470

parcel build index.html --public-url ./