javascript - How to determine if browser supports properties on event object? -

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some touch-enabled browsers (such mobile safari) have scale , rotation property available on event object events such touchmove.

i can detect support scale property so...

document.body.addeventlistener("touchmove", function(event) {     var supportsscaleproperty = !!event.scale; });

however, there way detect without having bind listener , property in callback?

for example, if worked?

var supportsscaleproperty = !!(new customevent("touchevents")).scale;

i tried looking @ createevent(), it's deprecated. looked @ new customevent(), wasn't sure string use touch events.

you may able use event constructor:

if ('scale' in new event("touchmove")) {     // has }

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