Simple PHP security

Although PHP security is outside of this course, I want to say a few words about it.
There are a number of JS and PHP attacks possible. Code injection is only one of them. Everybody is solving it differently (yes, usually checking the string for suspicious characters) since all possible inputs have different possible dangers. If you want something simple and you have a string input like "name" then you can check for the existence of various tags that shouldn't be there but might redirect the code if placed into the input doing something like:

$name = strip_tags( trim( $_POST[ 'name' ] ) );

The functions functions strip_tags() strips all HTML and PHP tags from a variable. Since we know that name is just the name of a person, and does not need links, or possibly malicious code, we don’t need any tags. So if a person was to add <a href=”http://www.mysite.com”>Mary</a>, it would only let the string ‘Mary’ to be assigned to the variable. The trim() function just strips any white space from beginning and end of the string ( actually it can do more - just google it for the future).