the veriabel $item is not defined how can they set it as src for the img

Mohammed,

To answer your questions:

1) PHP has a loop known as "foreach" that will iterate over each item in an array or each property of an object and allow you to perform some action on them (whatever code is inside your code block, i.e. the curly braces). The syntax of a "foreach" loop in PHP is as follows:

foreach( $array_or_object_name_here as $some_temporary_variable_name_here ) {
    // whatever code you want executed on each element/property goes here
}

So, if we have an array called $catalog that contains a bunch of images, we could write our foreach loop as follows:

foreach( $catalog as $current_image ) {
    // then again, in here, i write whatever code i want to execute on each element of the $catalog array (which i will be referring to as "$current_image" based on how i wrote the foreach declaration)
}

The key thing to understand here is that you're going to be going over every item in your array when using a foreach loop, and so in order to perform actions on the element that you're on currently, you need to have a temporary variable name declared for yourself to call. You can call it whatever you want; in the code example you provided, they chose the name "$item", in the code I just wrote, I chose the name "$current_image". That can be whatever you want, you just need something to refer to your current item as. Thus, the "$item" variable that they use IS set, and it's updated for EACH item in the array as your loop iterates over them one after the other. Thus, during the first cycle of your loop, the "$item" variable it set to equal the first element in your $catalog array, and has all of its properties available to use. Once the loop finishes with that element, it moves onto the next, and now "$item" refers to that second element in the $catalog array, and so forth until all of the elements have been handled.

2) The dots that you see are how PHP concatenates strings. In JavaScript, it's a "+" sign, which is a little more intuitive, but that's all the dots are doing. They allow you to jump in and out of strings and mash them together into one, which is what is happening in the code example.

Hope this helps to clear some things up!

Erik