<p>Here are some gems:</p>

<p>Literals:</p>

<pre><code>var obj = {}; // Object literal, equivalent to var obj = new Object();
var arr = []; // Array literal, equivalent to var arr = new Array();
var regex = /something/; // Regular expression literal, equivalent to var regex = new RegExp('something');
</code></pre>

<p>Defaults:</p>

<pre><code>arg = arg || 'default'; // if arg evaluates to false, use 'default', which is the same as:
arg = !!arg ? arg : 'default';
</code></pre>

<p>Of course we know anonymous functions, but being able to treat them as literals and execute them on the spot (as a closure) is great:</p>

<pre><code>(function() { ... })(); // Creates an anonymous function and executes it
</code></pre>

<p><strong>Question:</strong> What other great syntactic sugar is available in javascript?</p>

In Mozilla (and reportedly IE7) you can create an XML constant using:
```
var xml = <elem></elem>;
```
You can substitute variables as well:
```
var elem = "html";
var text = "Some text";
var xml = <{elem}>{text}</{elem}>;
```