Knockout綁定audio的pause事件致使音頻沒法中止

...時間過得真快, 一晃4天已通過去了, 然而本身並無動筆寫什麼. 自省.

看了看今天的工做, 感受好像沒什麼可寫的. 不由在想是否是一天一篇有點兒難. 再一想, 這分明就是在給本身找理由. 就是再短也應該把當天學到的任何東西整理一下, 怎麼都是有的寫的! 若是徹底沒得寫, 那我卻是要反思下我今天是否是太虛度了.

廢話很少說, 整理下這兩天的收穫. (最近一直寫code可是不多記錄, 提醒本身之後堅持記錄!)

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我發現我用knockout給audio元素綁定了pause事件, 形如<audio data-bind="event: { pause: pauseHandler }"...可是用$('audio').trigger('pause')沒法暫停audio播放. 很詭異.

因而我爲audio的play和pause事件都綁上了console.log, 發現trigger('play')會輸出兩次play而trigger('pause')只會輸出一個pause. 可是若是用.play()和.pause()就能夠正常地播放和中止音頻, 同時只會輸出一個play和pause.

爲何$('audio').trigger('play')會出發playHandler兩次而$('audio')[0].play()只會觸發一次?

搜索一陣無果就在stackoverflow上問了一下, 獲得的解答是:

trigger('play') triggers your handler programmatically, which dispatches the play event on the audio element, once the clip starts playing, the play event is dispatched again, triggering your handler a second time, whereas $('audio')[0].play() won't trigger your handler initially, it'll trigger the dom element's native play event, which, when it starts playing will trigger your handler

可是至於可否用trigger('play')只觸發一次playHandler, 並無獲得答覆.

爲何用Knockout綁定pause事件後沒法用trigger('pause')暫停音頻?

本身摸索出來了答案, 只要給pauseHandler加上return true;便可. 可是不明白爲何必需要這麼加, 因而問了一記, 本身才發現spec上寫得清清楚楚:

By default, Knockout will prevent the event from taking any default action....However, if you do want to let the default action proceed, just return true from your event handler function.