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Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 24 |
1 files changed, 22 insertions, 2 deletions
@@ -1065,18 +1065,38 @@ The framework has a built-in postMessage API that can be used when communicating <window>.postMessage( JSON.stringify({ method: 'slide', args: [ 2 ] }), '*' ); ``` +#### postMessage Events + When reveal.js runs inside of an iframe it can optionally bubble all of its events to the parent. Bubbled events are stringified JSON with three fields: namespace, eventName and state. Here's how you subscribe to them from the parent window: ```javascript window.addEventListener( 'message', function( event ) { var data = JSON.parse( event.data ); - if( data.namespace === 'reveal' && data.eventName ==='slidechanged' ) { + if( data.namespace === 'reveal' && data.eventName === 'slidechanged' ) { // Slide changed, see data.state for slide number } } ); ``` -This cross-window messaging can be toggled on or off using configuration flags. +#### postMessage Callbacks + +When you call any method via the postMessage API, reveal.js will dispatch a message with the return value. This is done so that you can call a getter method and see what the result is. Check out this example: + +```javascript +<revealWindow>.postMessage( JSON.stringify({ method: 'getTotalSlides' }), '*' ); + +window.addEventListener( 'message', function( event ) { + var data = JSON.parse( event.data ); + // `data.method`` is the method that we invoked + if( data.namespace === 'reveal' && data.eventName === 'callback' && data.method === 'getTotalSlides' ) { + data.result // = the total number of slides + } +} ); +``` + +#### Turning postMessage on/off + +This cross-window messaging can be toggled on or off using configuration flags. These are the default values. ```javascript Reveal.initialize({ |