Similar to HTML comments, XML comment has the following syntax:

<!-- Our comment -->

XML comment example in XML document:

<?xml version="1.0" encoding="UTF-8"?>
<student>
    <!-- Some comment about the student -->
    <first-name>George</first-name>
    <phone.mobile>(011) 123-4567</phone.mobile>
    <tive_language>English</tive_language>
    <another_tag>some text</another_tag>
    <city />
</student>

An empty element in XML document can be represented in two ways:

<?xml version="1.0" encoding="UTF-8"?>
<student>
   <name>George</name>
   <phone>(011) 123-4567</phone>
   <address></address>
   <city />
</student>

One way is

<address></address>

element and another is

<city />

. In other words, one with closing tag and another is self-closing tag.

version 

- specifies the version used in the XML document (1.0)

encoding

- defines the character encoding used in the XML document (UTF-8)

standalone

- if the value is

yes

it means there is no external declaration required to parse the document (yes)

XML references allow us to have symbols in XML text, that are not allowed to be included directly. References begin with the symbol

&

which is a reserved character and end with the symbol

;

XML has two types of references: ... 1.

Entity Reference

− which contains a name between the start and the end delimiters. For example

&

where amp is name. The name refers to

&

symbol. ... 2.

Character Reference

− contains reference, such as

A

contains a hash mark

#

followed by a number. The number refers to the Unicode code of a character. In this case, 65 refers to alphabet

A

Some characters are are not allowed in XML text because they are reserved by the XML itself. Hence, they cannot be used directly. If we need to include them in text, some replacement-entities are used. These symbols are:

<

- less than -

<

>

- greater than -

>

'

- ampersand -

&

"

- apostrophe -

'

&

- quotation mark -

"

Dynamically

changes HTML table content using XMLHttpRequest after choosing any option on

<select>

obj = { table: "customers", limit: 20 };
dbParam = JSON.stringify(obj);
xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
  if (this.readyState == 4 && this.status == 200) {
    myObj = JSON.parse(this.responseText);
    txt += "<table border='1'>"
    for (x in myObj) {
      txt += "<tr><td>" + myObj[x].name + "</td></tr>";
    }
    txt += "</table>"
    document.getElementById("demo").innerHTML = txt;
  }
}
xmlhttp.open("POST", "json_demo_db_post.php", true);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send("x=" + dbParam);

This command sets the

APP_KEY

value in our

.env file

for security purposes (for sessions and other encrypted data)

php artisan key:generate

We can remove or change the breadcrumb separator by assigning different value to

$breadcrumb-divider: none;

sass variable. We can even assign SVG icon using the following syntax

$breadcrumb-divider: url(data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI4IiBoZWlnaHQ9IjgiPjxwYXRoIGQ9Ik0yLjUgMEwxIDEuNSAzLjUgNCAxIDYuNSAyLjUgOGw0LTQtNC00eiIgZmlsbD0iY3VycmVudENvbG9yIi8+PC9zdmc+);

If we want to remove the separator, we assign

none

to the variable

$breadcrumb-divider: none;

The column in the middle has specified width and the rest of the space is divided equally for the other columns

<div class="container">
  <div class="row">
    <div class="col">
      1 of 3
    </div>
    <div class="col-6">
      2 of 3 (wider)
    </div>
    <div class="col">
      3 of 3
    </div>
  </div>
  <div class="row">
    <div class="col">
      1 of 3
    </div>
    <div class="col-5">
      2 of 3 (wider)
    </div>
    <div class="col">
      3 of 3
    </div>
  </div>
</div>

.container

class sets a max-width at each responsive breakpoint