手机 html5 hammer drag widget,javascript

I'm having trouble with the Hammer.js pinch function. The press function works wonderfully, but I'm trying to add a zoom in/zoom out function with Pinch. The app works fine without the pinch, until I add the mc.get('pinch') code. I've looked everywhere, can't find an answer. Please help :)

var myElement = document.getElementById('myCanvas');

var mc = new Hammer.Manager(myElement);

/*App does not load at all with this line of code*/

mc.get('pinch').set({ enable: true });

/****/

mc.add(new Hammer.Press({

event: 'press',

pointer: 1,

threshold: 20,

time: 10

}));

mc.add(new Hammer.Pinch({

event: 'pinch',

pointer: 2,

threshold: 10,

time: 10

}));

var diagnostics = 0;

mc.on("press", function(event)

{

x1 = event.center.x;

y1 = event.center.y;

});

mc.on("pinchout", function(event)

{

//This variable is declared.

diagnostics++;

});

mc.on("pinchin", function(event)

{

diagnostics--;

});

手机 html5 hammer drag widget,javascript - HTML5 Canvas Phonegap Hammer.js - Pinch