Use of Htmlentities, Addslashes, Htmlspecialchars

1. Html_entity_decode (): Converts an HTML entity to a character.

Eg:$str = "Just atest & & #039; Learn to use & #039; ";
echo Html_entity_decode ($STR);
echo "<br/>";
Echo Html_entity_decode ($str, ent_quotes);
echo "<br/>";
Echo Html_entity_decode ($str, ent_noquotes);

The output is as follows:

Just a Test & ' learn to use '
Just a Test & ' learn to use '
Just a Test & ' learn to use '

2. htmlentities (): Converts characters to HTML entities.

Eg:$str = "Just a Test & ' learn to use '";
Echo htmlentities ($str, Ent_compat);
echo "<br/>";
Echo htmlentities ($str, ent_quotes);
echo "<br/>";
Echo htmlentities ($str, ent_noquotes);

The output is as follows:

Just a Test & ' learn to use '
Just a Test & ' learn to use '
Just a Test & ' learn to use '

View the source code as follows:
Just a test &amp; ' Learn to use ' <br/>
Just a test &amp; & #039; learn to use& #039; <br/>
Just a test &amp; ' Learn to use '

3.addslashes (): Adds a backslash before the specified predefined character

Predefined characters include: Single quotation mark ('), double quotation mark ("), backslash (\), NULL

By default, PHP instruction MAGIC_QUOTES_GPC is on, and automatically runs Addslashes () for all get, POST, and cookie data. Do not use Addslashes () for strings that have been MAGIC_QUOTES_GPC escaped, because this results in double-layer escaping. You can use the function GET_MAGIC_QUOTES_GPC () to detect this situation.

Eg:$str 3= "\ just a" \ "test";
Echoaddslashes ($str 3);

Output:

\ \ just a \ ' \ "Test

4.stripslashes (): Remove the backslash added by the addslashes function

Eg:$str 4= "\ \ Just a \ '" Test ";
Echo stripslashes ($str 4);

Output:

Just a ' "test

5, Htmlspecialchars (): Convert some of the predefined characters to HTML entities.

Predefined characters include:& (and number) become &amp;
"(double quotes) become &quot;
' (single quotes) become & #039;
< (less than) becomes &lt;
> (greater than) becomes &gt;

Eg:$str 5 = "Just atest & ' Learn to use '";
Echo Htmlspecialchars ($str 5, Ent_compat);
echo "<br/>";
Echo Htmlspecialchars ($str 5, ent_quotes);
echo "<br/>";
Echo Htmlspecialchars ($str 5, ent_noquotes);

Output:

Just a Test & ' learn to use '
Just a Test & ' learn to use '
Just a Test & ' learn to use '

                &NBS P    just a test   &amp; & #039; learn to use& #039; <br/>
                     just a test  &amp; ' Learn to use '
6, htmlspecialchars_decode (): Converts some of the predefined HTML entities to characters.

 &quot; becomes "(double quotes)
 & #039; become ' (single quote)
 &lt; Become < (less than)
 &gt; becomes > (greater than)

eg: $str 6 = "Just atest  &amp; & #039; learn to use& #039; ";
echo  htmlspecialchars_decode ($str 6);
Echo   "<br/>";
Echo  htmlspecialchars_decode ($str 6, ent_quotes);
Echo   "<br/>";
Echo  htmlspecialchars_decode ($str 6, ent_noquotes);

Output:
Just a Test & ' learn to use '
Just a Test & ' learn to use '
Just a Test & ' learn to use '
View Source code:
Just a Test & & #039; Learn to use & #039; <br/>
just a Test & ' learn to use ' <br/>
just a Test & & #039; Learn to use & #039;

So far, I think you should understand the basic trial of several functions.

Use of Htmlentities, Addslashes, Htmlspecialchars