Understanding variable scopes in php

Question

echo "Point1, a=".$a."\n";
echo "Point1, b=".$b."\n";
if(1<2)
    {
        $a = 6; 
        $b['link'] = "here";
        echo "Point2, a=".$a."\n";
        echo "Point2, b[link]=".$b['link']."\n";
    }
echo "Point3, a=".$a."\n";
echo "Point3, b[link]=".$b['link']."\n";

Why does the above code print out the following?

Point1, a=
Point1, b=
Point2, a=6
Point2, b[link]=here
Point3, a=6
Point3, b[link]=here

In my understanding, the scope of $a and $b should end within the curly braces { }!

Answer 1

In my understanding, the scope of $a and $b should end within the curly braces { }!

Only functions and methods have their own, local scope. Other control structures (loops, conditions...) do not.

Variable scope in the PHP manual

Answer 2

The first $a and $b would actually throw a warning, undefined index as they haven't been declared before being output.