Javascript Bar

This section is here to document the inner workings of the client side debug bar. Nothing described below is needed to run the debug bar in a normal way.

The default client side implementation of the debug bar is made entirely in Javascript and is located in the debugbar.js file.

It adds a bottom-anchored bar which can have tabs and indicators. The bar can be in an open or close state. When open, the tab panel is visible. An indicator is a piece of information displayed in the always-visible part of the bar.

The bar handles multiple datasets by displaying a select box which allows you to switch between them.

The state of the bar (height, visibility, active panel) can be saved between requests (enabled in the standard bar).

Each panel is composed of a widget which is used to display the data from a data collector. Some common widgets are provided in the widgets.js file.

The PhpDebugBar namespace is used for all objects and the only dependencies are jQuery and FontAwesome (css). FontAwesome is optional but is used to add nice icons!

The main class is PhpDebugBar.DebugBar. It provides the infrastructure to manage tabs, indicators and datasets.

When initialized, the DebugBar class adds itself to the <body> of the page. It is empty by default.

Tabs and indicators

Controls (ie. tabs and indicators) are uniquely named. You can check if a control exists using isControl(name).

Tabs can be added using the createTab(name, widget, title) function. The third argument is optional and will be computed from the name if not provided.

var debugbar = new PhpDebugBar.DebugBar();
debugbar.createTab("messages", new PhpDebugBar.Widgets.MessagesWidget());

Indicators can be added using createIndicator(name, icon, tooltip, position). Only name is required in this case. icon should be the name of a FontAwesome icon. position can either be right (default) or left.

debugbar.createIndicator("time", "cogs", "Request duration");

You may have noticed that the data to use inside these controls is not specified at the moment. Although it could be specified when initialized, it is better to use data mapping to support dynamically changing the data set.

Data mapping

To enable dynamically changing the data sets, we need to specify which values should be feed into which controls. This can be done using setDataMap(map) which takes as argument an object where properties are control names. Values should be arrays where the first item is the property from the data set and the second a default value.

    "messages": ["messages", []],
    "time": ["time.duration_str", "0ms"]

You can notice that nested properties can also be accessed using the dot notation.

In this mapping, data["messages"] will be fed to the messages tab and data["time"]["duration_str"] will be fed to the time indicator.

Note: you can append mapping info using addDataMap(map)


Although you shouldn't have to do anything regarding managing datasets, it is interesting to know a few functions related to them.

addDataSet(data, id) adds a dataset to the bar. The select box that allows to switch between sets is only displayed if more than one are added. id is optional and will be auto-generated if not specified.

showDataSet(id) allows you to switch to a specific dataset.


Widgets should inherit from the PhpDebugBar.Widget class which is used as the base of every visual component in the debug bar.

New widgets can be created using extend():

var MyWidget = PhpDebugBar.Widget.extend({
    // class properties

The Widget class defines a set(attr, value) function which can be used to set the value of attributes.

Using bindAttr(attr, callback), you can trigger a callback every time the value of the attribute is changed. callback can also be a jQuery object and in that case it will use the text() function to fill the element.

Widgets should define a render() function which initializes the widget elements.

initialize(options) will always be called after the constructor.

var MyWidget = PhpDebugBar.Widget.extend({

    tagName: 'div', // optional as 'div' is the default

    className: 'mywidget',

    render: function() {
        this.bindAttr('data', this.$el);


// ----

debugbar.createTab("mytab", new MyWidget());
debugbar.addDataMap({"mytab": ["mydata", ""]});

Widgets for bundled data collectors are included as well as more generic widgets that you can build on top of. They are located in widgets.js in the PhpDebugBar.Widgets namespace.

Generic widgets:

Data collectors related widgets:

Custom tabs and indicators

Behind the scene, createTab() and createIndicator() use addTab(name, tab) and addIndicator(name, indicator). Tabs are objects of type PhpDebugBar.DebugBar.Tab and indicators of type PhpDebugBar.DebugBar.Indicator. These classes subclass PhpDebugBar.Widget which makes it easy to create custom tabs or indicators.

var LinkIndicator = PhpDebugBar.DebugBar.Indicator.extend({

    tagName: 'a',

    render: function() {
        this.bindAttr('href', function(href) {
            this.$el.attr('href', href);


// ----

debugbar.addIndicator('phpdoc', new LinkIndicator({ href: '', title: 'PHP doc' }));


An OpenHandler object can be provided using setOpenHandler(). The object is in charge of loading datasets. The only requirement is to provide a show() method which takes as only parameter a callback which expects an id and data parameter.

The default implementation is PhpDebugBar.OpenHandler which must be use in conjunction with the server side DebugBar\OpenHandler (see previous section).

debugbar.setOpenHandler(new PhpDebugBar.OpenHandler({ url: "open.php" }));