filter_var() function

Returns the input string filtered into the required typ, or FALSE if it was unable to perform the sanitization (e.g. due to illegal characters etc)

  if ( ($MyVariable = filter_var($EnteredEmail, FILTER_SANITIZE_EMAIL)) !== False )

See here for all the available filter options.

Example – INT

  if ( ($MyVariable = filter_var($SourceValue, FILTER_VALIDATE_INT, ["options" => ["min_range" => 18, "max_range" => 124]])) !== False )
  {

  }

Sanitising for HTML from a form POST

If server magic quotes is turned on then it will add / before a single and double quotes in the text, so strip them out first:

  $MyTextField = trim($_POST['MyTextField']);
  $MyTextField = stripslashes($MyTextField);
  $MyTextField = htmlspecialchars($MyTextField, ENT_QUOTES);

\n new line characters will still be stored as \n (htmlspecialchars() doesn’t convert them to <br>). You can convert them now using nl2br() or when you display the text again (usually better to do when displaying as HTML, not when storing to db).

  $MyTextField = nl2br($MyTextField);

When outputting multiline text – Convert \n character to <br> when displaying text within page html output

  $MyTextField = Results['MyTextField'];
  $MyTextField = nl2br($MyTextField);    //Convert '\n' to <br>

Removing new lines in a text box

$MyText = str_replace("\r\n"," ", $MyText);
$MyText = str_replace("\n"," ", $MyText);

Removing other characters

  $MyTextField = str_replace("\t"," ", $MyTextField);

Other slashes functions that are available

stripcslashes()