Simple Server-Side String Interpolation. Demo: http://jsbin.com/pipudujixo/1/edit. Requires safeGet() here: https://gist.github.com/cerebrl/a52b69aafa9bf820bb1e

safeInterpolate.js

/* Simple, Server-Side String Interpolation
 * Base on John Resig's Microtemplating: http://ejohn.org/blog/javascript-micro-templating/
 *
 * @param str {String} A string with key or object path in handlebar-like syntax: e.g. {{user.name}} 
 * @param data {Object} The data source with with to grab the key matching values
 * @return {String} The final string with key-value replacements
 */
var safeInterpolate  = function safeInterpolate (str, data){
	// Create a new function with the template converted into executable code.
	var fn = new Function("obj",

		// The array to which the strings will be pushed.
		"var p=[];" +

		// Introduce the data as local variables using with()
		"with (obj) {" +

			"p.push('" +
				// Convert the template into an array of pure strings and values.
				// If item is a key, do a safeGet() to grab the value
				str.replace(/[\r\t\n]/g, " ") // Normalize whitespace
					.split("{{").join("\t") // Split string on the opening template key notation
					.replace(/\t(.*?)}}/g, "',safeGet(obj, '$1'),'") + // Grabs the object key or dot notated path
				"');" + // Close push syntax
			"}" +
			// Converts the array to a final string. 
		"return p.join('');");

	return data ? fn(data) : str;
};