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    <blockquote> <p>assuming that the parsing goes from top to bottom, setSquare isnt defined yet so shouldn't it return an error?</p> </blockquote> <p>Function declarations are <em>hoisted to the top</em> of the containing scope. <code>function setSquare() {}</code> is a function declaration, so your code is effectively the same as declaring the function before the loop:</p> <pre><code>function setSquare (thisSquare) { //... } for(var i=0; i&lt;24; i++){ setSquare( i ) } </code></pre> <blockquote> <p>how does javascript know that "square" in function 2 is a id and not a string?</p> </blockquote> <p>It does not. It is a string and is treated as such. There is nothing like an "id datatype" in JavaScript. <code>currSquare</code> is a variable containing the string <code>"squareX"</code> where X is the value from <code>thisSquare</code> (0 to 23).</p> <blockquote> <p>there IS no ID on main page of <code>currSquare</code> so how can it "get" it</p> </blockquote> <p><code>document.getElementById</code> expects a string as argument. This string should be an id of some element. There is nothing special about this. Instead of passing a literal string, you are passing the one contained in <code>currSquare</code> (just like you pass the integer contained in <code>i</code> to <code>setSquare</code>).</p> <hr> <p>It seems you have not fully understood the basics yet, although your are doing a tutorial. Maybe the <a href="https://developer.mozilla.org/en/JavaScript/Guide" rel="nofollow"><em>MDC JavaScript Guide</em></a> will help you more. Read especially about <a href="https://developer.mozilla.org/en/JavaScript/Guide/Values,_Variables,_and_Literals" rel="nofollow"><em>Values, Variables, and Literals</em></a> and <a href="https://developer.mozilla.org/en/JavaScript/Reference/Functions_and_function_scope" rel="nofollow"><em>Functions and function scope</em></a>.</p>
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    1. POlearning javascript, need clarification on variables values
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    1. USFelix Kling
    1. USFelix Kling
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    1. COThanks Felix. let me ask u another? based on your comment above "There is nothing like an "id datatype". so since in my html i have an id of the area i want affected, how does JS know to choose that id selector i defined in html and not say , some random sentence with the word "square" in it.? thanks again schoolin a noob
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    2. CO@somdow: Because `document.getElementById` is defined like that. It searches for an HTML element which has an attribute `id` equal to the name you passed to the function. It does inspect any content or other attributes. [You can find more information here](https://developer.mozilla.org/en/DOM/document.getElementById). Other functions are for example, `document.getElementsByTagName`, which returns a list of elements with a certain tag. E.g. `document.getElementsByTagName('a')` would return all links.
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      1. USFelix Kling
 

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