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From: Cezary Tomczyk <cezary.tomczyk@gmail.com>
Newsgroups: comp.lang.javascript
Subject: Re: Inserting stuff received with AJAX into the DOM
Date: Mon, 21 Aug 2017 17:24:26 +0200
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On 21/08/2017 16:44, Thomas 'PointedEars' Lahn wrote:
> Cezary Tomczyk wrote:
> 
>> On 20/08/2017 22:39, Thomas 'PointedEars' Lahn wrote:
>>> Cezary Tomczyk wrote:
>>>> On 20/08/2017 19:18, Thomas 'PointedEars' Lahn wrote:
>>>>> Cezary Tomczyk wrote:
>>>>>> "par" is always defined, […]
>>>>> How did you get that idea?
>>>> const par = document.createElement( 'p' );
>>> And you are sure that the method that is called on the right-hand side of
>>> that assignment cannot possibly return something else than a reference to
>>> an object that has a method named “appendChild”?
>>
>> I am sure that:
>>
>> const par = document.createElement( 'p' );
>>
>> will always create HTML element. I can't see any real scenario where
>> createElement method will return "something else than a reference to an
>> object that has a method named “appendChild”" in that particular scenario.
> 
> Why?

https://developer.mozilla.org/en-US/docs/Web/API/Document/createElement

"In an HTML document, the Document.createElement() method creates the 
HTML element specified by tagName, or an HTMLUnknownElement if tagName 
isn't recognized. In a XUL document, it creates the specified XUL 
element. In other documents, it creates an element with a null namespace 
URI."

In that particular case:

const par = document.createElement( 'p' );

this will return an HTML p element.

As for "something else than a reference to an object that has a method 
named “appendChild”" may occur, of course, but this is a very rare case 
I would say and even, if it'll occur then calling "appendChild" later 
will throw a DOM exception which I think it's good because it helps to 
catch the error on an early stage.

I just don't see a benefit of using "if" statement here instead of simple:

par.appendChild(text);

>> Correct me, if I am wrong.
> 
> Nice try :)

:-)

-- 
Cezary Tomczyk
http://www.ctomczyk.pl/