Add rest of using-jquery-core section

Author: danheberden

content/jquery-fundamentals/using-jquery-core/avoid-conflicts-other-libraries.md

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+---
+chapter : jquery-core
+section : 6
+title   : Avoiding Conflicts with Other Libraries
+attribution:  jQuery Fundamentals
+---
+## Avoiding Conflicts with Other Libraries
+
+If you are using another JavaScript library that uses the `$` variable, you can run into conflicts with jQuery. 
+In order to avoid these conflicts, you need to put jQuery in no-conflict mode immediately after it is loaded onto the page and before you attempt to use jQuery in your page.
+
+When you put jQuery into no-conflict mode, you have the option of assigning a variable name to replace `$`.
+
+<div class="example" markdown="1">
+Putting jQuery into no-conflict mode
+
+    &lt;script src="prototype.js">&lt;/script>
+    &lt;script src="jquery.js">&lt;/script>
+    &lt;script>var $j = jQuery.noConflict();&lt;/script>
+</div>
+
+You can continue to use the standard $ by wrapping your code in a self-executing anonymous function; 
+this is a standard pattern for plugin authoring, where the author cannot know whether another library will have taken over the `$`.
+
+<div class="example" markdown="1">
+Using the $ inside a self-executing anonymous function
+
+    &lt;script src="prototype.js">&lt;/script>
+    &lt;script src="jquery.js">&lt;/script>
+    &lt;script>
+    jQuery.noConflict();
+    
+    (function($) {
+       // your code here, using the $
+    })(jQuery);
+    &lt;/script>
+</div>

content/jquery-fundamentals/using-jquery-core/checking-types.md

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+---
+chapter : jquery-core
+section : 3
+title   : Checking types
+attribution:  jQuery Fundamentals
+---
+## Checking types
+
+As mentioned in the "JavaScript basics" section, jQuery offers a few basic utility methods for determining the type of a specific value.
+
+<div class="example" markdown="1">
+Checking the type of an arbitrary value
+
+    var myValue = [1, 2, 3];
+    
+    // Using JavaScript's typeof operator to test for primative types
+    typeof myValue == 'string'; // false
+    typeof myValue == 'number'; // false
+    typeof myValue == 'undefined'; // false
+    typeof myValue == 'boolean'; // false
+    
+    // Using strict equality operator to check for null
+    myValue === null; // false
+    
+    // Using jQuery's methods to check for non-primative types
+    jQuery.isFunction(myValue); // false
+    jQuery.isPlainObject(myValue); // false
+    jQuery.isArray(myValue); // true
+</div>

content/jquery-fundamentals/using-jquery-core/data-methods.md

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+---
+chapter : jquery-core
+section : 4
+title   : Data Methods
+attribution:  jQuery Fundamentals
+---
+## Data Methods
+
+As your work with jQuery progresses, you'll find that there's often data about an element that you want to store with the element. 
+In plain JavaScript, you might do this by adding a property to the DOM element, but you'd have to deal with memory leaks in some browsers. 
+jQuery offers a straightforward way to store data related to an element, and it manages the memory issues for you.
+
+<div class="example" markdown="1">
+Storing and retrieving data related to an element
+
+    $('#myDiv').data('keyName', { foo : 'bar' });
+    $('#myDiv').data('keyName'); // { foo : 'bar' }
+</div>
+
+You can store any kind of data on an element, and it's hard to overstate the importance of this when you get into complex application development. 
+For the purposes of this class, we'll mostly use `$.fn.data` to store references to other elements.
+
+For example, we may want to establish a relationship between a list item and a div that's inside of it. 
+We could establish this relationship every single time we interact with the list item, but a better solution would be to establish the relationship once, and then store a pointer to the div on the list item using `$.fn.data`:
+
+<div class="example" markdown="1">
+Storing a relationship between elements using `$.fn.data`
+
+    $('#myList li').each(function() {
+        var $li = $(this), $div = $li.find('div.content');
+        $li.data('contentDiv', $div);
+    });
+    
+    // later, we don't have to find the div again;
+    // we can just read it from the list item's data
+    var $firstLi = $('#myList li:first');
+    $firstLi.data('contentDiv').html('new content');
+</div>
+
+In addition to passing `$.fn.data` a single key-value pair to store data, you can also pass an object containing one or more pairs.

content/jquery-fundamentals/using-jquery-core/feature-browser-detection.md

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+---
+chapter : jquery-core
+section : 5
+title   : Feature & Browser Detection
+attribution:  jQuery Fundamentals
+---
+## Feature & Browser Detection
+
+Although jQuery eliminates most JavaScript browser quirks, there are still occasions when your code needs to know about the browser environment.
+
+jQuery offers the `$.support` object, as well as the deprecated $.browser object, for this purpose.
+ For complete documentation on these objects, visit [http://api.jquery.com/jQuery.support/](http://api.jquery.com/jQuery.support/ "$.support documentation on api.jquery.com") and [http://api.jquery.com/jQuery.browser/](http://api.jquery.com/jQuery.browser/ "$.browser support on api.jquery.com").
+
+The `$.support` object is dedicated to determining what features a browser supports; it is recommended as a more “future-proof” method of customizing your JavaScript for different browser environments.
+
+The `$.browser` object was deprecated in favor of the `$.support` object, but it will not be removed from jQuery anytime soon. It provides direct detection of the browser brand and version.