Wrapper around jquery template that allows

jquery.templatewrapper.js

    //
    // This is a wrapper around the jquery template library.
    //
    // The function to notice is:
    //   applyTemplate(data/{}, target/DOMNode, 
    //       callback/function, keepPreviousTemplate/boolean)
    // Once a template is instanced, calling this function will apply 
    //  the template with the given data, then call the callback with 
    //  no arguments.
    //
    // args should include any (1) of the following: url, templateString, template.
    // If these aren't good enough for you, override _init (and remember to set ready).
    //
    // You can also override isCachingEnabled to avoid caching (jsps/dynamic happy).
    //
    // Requires a cache (see https://gist.github.com/806462)
    //
    $.templateWrapper = function(args) {
		this.isCachingEnabled = true;
        this.applyTemplate = function(data, target, callback, keepPreviousTemplate) {
			this.getTemplate(function(template) {
		        this._applyTemplate(template, data, target, keepPreviousTemplate);
		        if (callback) {
		            callback();
		        }
			});
        };
        this._applyTemplate = function(template, data, target, keepPreviousTemplate) {
            if (!keepPreviousTemplate) {
                target.html("");
            }
            $.tmpl(template, data).appendTo(target);
        };
        this.getTemplate = function(callback) {
            if (this.template) {
				callback(this.template);
            } else if (this.templateString) {
				this.template = $.template(that.templateString));
				callback(this.template);
            } else if (this.url) {
				if (this.isCachingEnabled) {
					var cache = $.templateWrapper.urlCache = 
							$.templateWrapper.urlCache || $.udel.cache();
					cache.getput(this.url, this.loadTemplate, callback);
				}
				else {
					this.loadTemplate(callback);
				}
			}
		};
		this.loadTemplate = function(callback) {
            var that = this;
            $.ajax({
                dataType: "text",
                url: that.url,
                type: "GET",
                ifModified: that.isCachingEnabled,
                success: function(tmplString) {
					that.template = $.template(tmplString);
					callback(that.template);
                },
                error: function() {
					that.template = "Error loading template from url.";
					callback(that.template);
                }
            });
        };
        $.extend(true, this, args);
        this._init();
    };