Why is the regular expression not working as expected?

Question

JavaScript

Hello, I need help with a regular expression.

The function should return trueonly if strit is a closed tag htmlwithout indents and symbols (letters) both before the tag and after the tag or , for example. Now it returns if there are characters after the tag. How to fix it? I tried different methods, looked through the forums in search of solutions, both Russian and English. Found a solution:<img />true

function isHTML(str) {
                return /<(br|basefont|hr|input|source|frame|param|area|meta|!--|col|link|option|base|img|wbr|!DOCTYPE).*?>|<(a|abbr|acronym|address|applet|article|aside|audio|b|bdi|bdo|big|blockquote|body|button|canvas|caption|center|cite|code|colgroup|command|datalist|dd|del|details|dfn|dialog|dir|div|dl|dt|em|embed|fieldset|figcaption|figure|font|footer|form|frameset|head|header|hgroup|h1|h2|h3|h4|h5|h6|html|i|iframe|ins|kbd|keygen|label|legend|li|map|mark|menu|meter|nav|noframes|noscript|object|ol|optgroup|output|p|pre|progress|q|rp|rt|ruby|s|samp|script|section|select|small|span|strike|strong|style|sub|summary|sup|table|tbody|td|textarea|tfoot|th|thead|time|title|tr|track|tt|u|ul|var|video).*?<\/\2>/i.test(str) && !!$(str)[0];
            }

Thank you.

Answer 1

because .*
and any conditions fall under it