Starting with a baffling error---talking about the DOM node creation of jquery

There is a string like this: var s = '

How do I get the content value from jquery?

It would have been a simple question, either through regular fetching or by jquery's $ to turn the string into a JQ object to get. But that was the way it was later, but it brought problems.

In my understanding, the method of locating content should be $ (s). Find ("meta"). attr ("content"), but it is not correct to get the results.

So I made a simple attempt:

var s = ' This is a bit strange, the wind big guess is because there is But is this really the right result? Another simple attempt was made:
var s = ' <div>
The reason for this problem, I believe only jq source can give me the answer. Write a few lines of simple test code, go through the breakpoint to read the processing mechanism of JQ:
(function () {        debugger;        $ (' 
It turns out that the latter two are able to get the results correctly, except that the first method does not get the results correctly. This was finally clarified by studying the code created on the JQ object in the JQ source.
JQ will make a regular pass on the incoming string:
var parsed = rsingletag.exec (data);//rsingletag=/^< (\w+) \s*\/?> (?: <\/\1>|) $/
Explain the regular:
^< (\w+) \s*\/?
Start with <, followed by at least one character and any whitespace characters, followed by 0 or 1 times/
>
This will not be said, the above add up is <div > this or <meta/> such
(?: <\/\1>|) $
Can match <, one/or blank and end with
These are </div> or follow the <br/>. The empty behind the self-closing label
This way, if there are no strings of attributes and child nodes (such as ' 
if (parsed) {            return [Context.createelement (Parsed[1])];        } Context for contexts
Instead of passing the node's string, the string is placed into the DIV's innerhtml by creating a div node:
TMP = TMP | | Safe.appendchild (Context.createelement ("div"));//create divdom node tmp.innerhtml = wrap[1] + elem.replace (Rxhtmltag, "<$ 1></$2> ") + wrap[2];//to place the string into the innerHTML of the Div object
The browser does not allow the div to include the 
When the HTML is filtered, the string just now becomes:
JQ will look in the middle to find the end of the node, where the closing tag is looked for as a meta tag.
This is all the conclusions that have been made this time, to summarize:
If your tag is a label that does not have child nodes and attributes, JQ will create the node directly in your incoming context after the regular decision.
If you have a tag with a child node or attribute, the JQ regular will then create a div, pass your string as the innerHTML of the Div, then traverse the attributes and nodes inside the DOM node of the Div, get the class ID, and then create the real node.
However, the browser does not allow any non-frame elements inside the HTML tags, will be filtered.
After filtering the HTML tag, the head tag and the body tag are two tags, and JQ is looking for the label of the package from the outside, so these two tags are not recognized, and the META tag is self-closing tag, and is also the outermost enclosing tag from the inside of the package, So it becomes the tag that gets it.
That's probably it.
Starting with a baffling error---talking about the DOM node creation of jquery