(public).sospep.subjects ~ view article ~ 006-global

<h1 style="text-align: center;">global</h1>
<h2>[WHAT]</h2>
<ol>
<li>] the term 'global' can refer to&nbsp;different things in javascript&nbsp;</li>
<ol>
<li>] the <em><strong>global object</strong></em> - a&nbsp;native javascript object that 'contains' all the variables that have global scope, as well as its own properties and methods. This object exists for all javascript pages.</li>
<li>] OR</li>
<li>]&nbsp;<em><strong>a 'variable that has global scope'</strong></em> - meaning that&nbsp;the variable&nbsp;can be accessed from anywhere within your web page/site</li>
</ol></ol>
<h2>[WHY]</h2>
<ol>
<li>] <em>the global object</em></li>
<ol>
<li><em>] </em></li>
</ol>
<li>] global variables</li>
<ol>
<li>] typically you want to avoid using global variables</li>
</ol></ol>
<h2>[WHY NOT]</h2>
<ol>
<li><strong>] global variables</strong></li>
<ol>
<li>] any javascript code can access, read or write, the value of any&nbsp;global variables</li>
<li>] namespace pollution - the more you use global variables, the more likely that a naming conflict, which&nbsp;will result in NO errors but&nbsp;some unpredictable &nbsp;</li>
</ol></ol>
<h2>[WHERE]</h2>
<ol>
<li><strong>] <a href="/view/article?id=2706" target="_blank">global object</a> </strong></li>
<ol>
<li>] a complete listing of the properties and methods of the Global object</li>
</ol></ol>
<h2>[WHEN]</h2>
<ol>
<li>] global object</li>
<ol>
<li>] everywhere - exists for each javascript, created automatically</li>
</ol>
<li>] global variables</li>
<ol>
<li>] avoid</li>
</ol></ol>
<h2>[EXAMPLE]</h2>
<ol>
<li>]</li>
</ol>
<h2>[HOW-TO]</h2>
<ol>
<li>] use the var keyword to specify that your variable will be local to the function that is declared in.</li>
<li>] var x = "name"; // var will be "local"&nbsp;to the&nbsp;function where it is declared</li>
<li>] x = "name";&nbsp;// var will have global scope</li>
<li>] var x= "name"; // declared outside&nbsp;of any function would also have&nbsp;global scope&nbsp;</li>
</ol>
<h2>[REFERENCE]</h2>
<ol>
<li>] <a href="https://gist.github.com/hallettj/64478">https://gist.github.com/hallettj/64478</a>&nbsp;- a tutorial demonstrating why global variables are bad</li>
</ol><hr /><ol>
<li>] ?? - helloWorld scope / global object</li>
<li>] EX js-101-a&nbsp;</li>
</ol>

~ view article ~ Chapter] ch-002-learning-javascript FROM [ Book] language-javascript IN [ libraries] technology-developer-www