Mousetrap is a dependency-free JavaScript library for binding keyboard shortcuts.

Mousetrap, weighing only 1.4kb compressed, makes shortcut binding impressively effective.

We aren’t that fond of snippets, but here’s some code that shows how succinct and simple the library is:

Mousetrap.bind('ctrl+s', function(e) {
 _saveDraft(); 
});

Even if you don’t have the need for keyboard shortcuts now, do bookmark Mousetrap so it’s there when the need arises.

Placeholder is a plugin for rendering HTML5′s placeholder text as an overlay if it isn’t supported.

placeholder works by placing a “dissolving” span element on top of the input; this allows to keep form validation from breaking.

The plugin is useful to anyone looking for a backwards-compatible way of adding placeholders to their website.

Holder.js is a library for generating image placeholders.

Its use is very simple, requiring you to add only an img tag and specify the required dimensions of the placeholder.

The placeholders can be customized quite a lot — there are three default themes, and you can add new ones –, and the plugin can be set to run only in a specific location of the website.

NVD3.js is a library built in an attempt to provide a set of reusable charts and chart components created with d3.js.

The goal here is to keep the components adjustable to the user’s needs, and thus avoid the library slumping into cookie cutter pitfalls.

NVD3.js is being updated on the go, so expect many more awesome components from the community.

Select2 is a jQuery-based replacement for select boxes.

Select2 sports an impressive feature set:

• Infinite scrolling;
• Search and search results;
• Remote data sets;
• Built-in tagging support;
• etc.

Select2 is an impressive, full-blown library that is great for almost any advanced (or not so) web app.

string.js is a JavaScript library that adds extra string methods.

String manipulation is a daunting task, especially if you don’t know where to start, and string.js is just about the perfect library for everyday string manipulation tasks.

As everyone — I really mean everyone — who is a JS developer, needs to do some string magic at some time, and sometimes it’s hard to get through the logic and syntax through it.

String.js features several welcome methods for string manipulation:

• Capitalize;
• Collapse Whitespaces;
• Add dashes;
• Determine if a string has some term in it;
• etc.