if( $var == 1 ) {
    doSomething();
}
if( $var == 1 ) {
    doSomethingElse();
}

##</code><code>##

if( $var == 1 ) {
    doSomething();
    doSomethingElse();
}

##</code><code>##

if( $var1 == 1 ) {
    if( $var2 == 2 ) {
         doSomething();
    }
}

##</code><code>##

if( $var1 == 1 && $var2 == 2 ) {
     doSomething();
}