(public).sospep.subjects ~ view article ~ 004-this

<h1 style="text-align: center;">&nbsp;</h1>
<h1 style="text-align: center;">this</h1>
<h2>[WHAT]</h2>
<ol>
<li>]&nbsp;this - is a keyword in the javascript (and other) programming languages</li>
<li>] this - is used as a shortcut reference to refer to the current object,</li>
<li>] this - 'refers' to the object that invokes the call to this <span style="text-decoration: line-through;">...., ( aka the currently active object )</span></li>
<ol>
<li><strong>] First, know that all functions in JavaScript have properties, just as objects have properties. </strong></li>
<li><strong>] And when a function executes</strong>, it gets the <em>this</em> property</li>
<li>&mdash;a variable with the <strong>value of <em>the object</em> that invokes the function where <em>this</em> is used</strong>.(SRC = 1)</li>
</ol>
<li>] <em>this</em> reference ALWAYS refers to (and holds the value of) an object&mdash;a singular object&mdash;and</li>
<li>] this is usually used inside a function or a method,</li>
<li>] this can be used outside of a function in the global scope.</li>
<li>] this has some <strong>'gotchas'</strong> which can make it a 'bit tricky/trickier/? to work with' in some cases</li>
<ol>
<li>] this - inside a closure,</li>
<li>] this - global scope</li>
<li>] this - strict mode - Note that when we use <strong>strict mode</strong>, <em>this</em> holds the value of <em>undefined</em> in global functions and in anonymous functions that are not bound to any object.</li>
</ol>
<li>] RELATE = ] scope, ] call, apply, bind, $.proxy()</li>
</ol>
<h2>[WHY]</h2>
<ol>
<li>]</li>
<li>] this is used to refer to || reference the 'currently active'&nbsp;object</li>
<li>] shorthand,</li>
<ol>
<li>[] see example 1</li>
</ol>
<li>] the POWER of</li>
<ol>
<li>[] this lies WHERE you dont know the reference to something, ie a web&nbsp;page has 20 links, i dont know which link the user will click, BUT&nbsp;i can write 1 'link click' function and THEN using the&nbsp;'this' function i could get the value of the link that you the user&nbsp;clicked, var youClicked =&nbsp;this.id; and avoid the pain of having to write an individual link click function for each link on the page</li>
</ol>
<li>&nbsp;</li>
</ol>
<h2>[WHERE]</h2>
<ol>
<li>] * this is assigned a value when an object invokes the function where this is defined</li>
</ol>
<h2>[WHEN]</h2>
<ol>
<li>]</li>
<li>]</li>
</ol>
<h2>[EXAMPLE]</h2>
<ol>
<li>] to get a reference to the current pages title, i could use&nbsp;</li>
<ol>
<li>] var t = document.title;&nbsp;&nbsp; OR because the window object has the current</li>
<li>] var t = this.title; &nbsp;</li>
</ol></ol>
<h2>[HOW-TO]</h2>
<ol>
<li>] the important part is knowing what .this is referring to at the time you are referencing it</li>
</ol>
<h2>[REFERENCE]</h2>
<ol>
<li>[] <a href="http://javascriptissexy.com/understand-javascripts-this-with-clarity-and-master-it/%20" target="_blank">understand javascripts this with clarity and master it</a></li>
<ol>
<li>[] by Richard Bovine @javascriptissexy.com -&nbsp; an in depth concise and clear explanatory article on using / understanding this</li>
</ol>
<li><strong>[] NEW&nbsp; </strong><a href="http://javascript.info/object-methods" target="_blank">Object methods, " this"</a></li>
<ol>
<li>[]&nbsp; by __ @ javascript.info -</li>
</ol>
<li>[]</li>
</ol>
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~ view article ~ Chapter] ch-002-learning-javascript FROM [ Book] language-javascript IN [ libraries] technology-developer-www