Why, if I have a certain encoding format, do special characters appear (ñ and é)?

you can try the following

<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">

If you work in a system with a variety of technologies (php, html, javascript, bbdd, remote calls) you save yourself a lot of problems if you manage everything in the same code. That includes in the case that you work with ´utf-8`:

• Make sure your editor saves all files in utf-8
• Declare use of utf-8 in html files
• Declare use of utf-8 in DB tables
• Consider transferring data with XML declaring utf-8 in the header
• If you take access to services of another encoding, implement a cast on the input

When you see ñ, that is the ISO-8859 representation of a ñutf-8 encoded one, if it is shown to you on a utf-8 page it means that the source of the text was originally utf-8, then it was because of an artifact interpreted as ISO and finally reconverted to utf-8.

If you want particular help like making sure you work with utf-8, add a list of the artifacts and tools you use to your question and you might get concrete answers like changing the encoding of this part of your system to utf-8.

To find the source of the errors you have to find out where these texts come from:

• Password and ID: (html)
• Enter the password and ID

If for example the first text is a fixed text in an html file, it means that the file is saved in utf-8, but the page is displayed with ISO-8859.

If the second text is fixed text in your html file, it may be that the html encoding and configuration are the same, still you can't be sure if it's ISO-8859 or utf-8.

To begin with, I recommend that you make sure that all files with fixed texts are saved in utf-8, then see how they are displayed.

If you are using html5 it is better to use this other meta tag:

<meta charset="utf-8" />

What I did to solve after reading @StefanNolde's good answer, was the following:

It seems to me that it solves but I think it could be made simpler

• In my PHP header use:<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">

This helped me so that <?>the accents for the database values ​​came out like thiséjemploñ

• In my DB change the collation toUTF-8_spanish_ci

I suppose it helps that it is collated in Spanish and not in Swedish as it was

• Sublime text uses WESTERN, which is a combination (something like that I understood) of encoding between UTF-8, UTF-16and another one, placing UTF-8 by default in the files.

There was no problem with saving the files

• Use UNICODEto generate the special characters in Javascript

  \u00e1 -> á \u00e9 -> é \u00ed -> í \u00f3 -> ó \u00fa -> ú \u00c1 -> Á \u00c9 -> É \u00cd -> Í \u00d3 -> Ó \u00da -> Ú \u00f1 -> ñ \u00d1 -> Ñ \u00BF -> ¿

It allows me to make alerts with questions, accents in the words and the letter eñe,"\u00BFEsta seguro que desea cambiar la contrase\u00f1a?"

• In HTML/PHP the words that were in the document come out with accents and special characters such as ñ, there was no problem in some documents, for those that presented the absence of accents and eñe, use: &LETRAacute;and &LETRATilde;.

It allowed to obtain something like this: Occurred and Password applying: OcurrióandContraseñ