$id

[Xtremer360]

What does this mean?

 

if ($id !='') 

[Psycho]

It is a conditional check to test if the variable $id does not equal an empty string.

[Xtremer360]

So to rephrase it's checking to make sure it has a value?

[Psycho]

So to rephrase it's checking to make sure it has a value?

 

Not exactly. An empty string IS a value. There are many variations of what the lay person would consider an empty value. But, programatically speaking there can be significant differences based upon the context. Here are some examples:

 

Undefined variable (variable has not been created)

Null variable (variable is created but no value is assigned)

Empty string (A variable which holds an empty string value)

False value (a variable with a boolean false value)

The value zero (0) (a variable with the value 0 - can be interpreted as false in some conditions)

 

So, as I stated it is testing if the variable $id is NOT an empty string. If the variable was set to Null, false, or was undefined that test would return true just as if the value was "foo"