Cosmicist/index.html

## index.html
<!doctype html>
<html>
    <head>
        <meta charset="utf-8">
        <title>String format</title>
    </head>
    <body>
        <h2>Default</h2>
        <p>
            <pre>Replacing &lt;strong&gt;{foo}&lt;/strong&gt; and &lt;strong&gt;{bar}&lt;/strong&gt;</pre>
            <span id="format">Replacing <strong>{foo}</strong> and <strong>{bar}</strong></span>
        </p>

        <h2>Custom regex</h2>

        <dl>
            <dt>Regex</dt>
            <dd>/:(\w+)/ig</dd>

            <dt>Format</dt>
            <dd><pre>Replacing &lt;strong&gt;:foo&lt;/strong&gt; and &lt;strong&gt;:bar&lt;/strong&gt;</pre></dd>
        </dl>

        <p>
            <span id="custom">Replacing <strong>:foo</strong> and <strong>:bar</strong></span>
        </p>

        <script src="string.format.js"></script>
        <script>
        var el = document.getElementById('format');
        el.innerHTML = el.innerHTML.format({foo: 'this', bar: 'that'});

        var el = document.getElementById('custom');
        el.innerHTML = el.innerHTML.format({foo: 'this', bar: 'that'}, /:(\w+)/ig);
        </script>
    </body>
</html>

## string.format.js
"use strict";

(function()
{
    String.prototype.format = function(reps, regex) {
        if (typeof regex == 'undefined' || regex.constructor !== RegExp) {
            var regex = /\{(\w+)\}/ig;
        }

        var m, str = this;
        while((m = regex.exec(str)) !== null) {
            str = str.replace(m[0], reps[m[1]]);
        }

        return str;
    }
})();
	<!doctype html>
	<html>
	<head>
	<meta charset="utf-8">
	<title>String format</title>
	</head>
	<body>
	<h2>Default</h2>
	<p>
	<pre>Replacing <strong>{foo}</strong> and <strong>{bar}</strong></pre>
	<span id="format">Replacing <strong>{foo}</strong> and <strong>{bar}</strong></span>
	</p>

	<h2>Custom regex</h2>

	<dl>
	<dt>Regex</dt>
	<dd>/:(\w+)/ig</dd>

	<dt>Format</dt>
	<dd><pre>Replacing <strong>:foo</strong> and <strong>:bar</strong></pre></dd>
	</dl>

	<p>
	<span id="custom">Replacing <strong>:foo</strong> and <strong>:bar</strong></span>
	</p>

	<script src="string.format.js"></script>
	<script>
	var el = document.getElementById('format');
	el.innerHTML = el.innerHTML.format({foo: 'this', bar: 'that'});

	var el = document.getElementById('custom');
	el.innerHTML = el.innerHTML.format({foo: 'this', bar: 'that'}, /:(\w+)/ig);
	</script>
	</body>
	</html>
	"use strict";

	(function()
	{
	String.prototype.format = function(reps, regex) {
	if (typeof regex == 'undefined' \|\| regex.constructor !== RegExp) {
	var regex = /\{(\w+)\}/ig;
	}

	var m, str = this;
	while((m = regex.exec(str)) !== null) {
	str = str.replace(m[0], reps[m[1]]);
	}

	return str;
	}
	})();