How exactly does an image element's `complete` property work?

后端 未结 2 1076
佛祖请我去吃肉
佛祖请我去吃肉 2021-02-08 20:20

I have ran into a bit of a problem with my understanding of the complete property.

I assumed complete would be true if the image has been downl

2条回答
  •  礼貌的吻别
    2021-02-08 20:52

    From the w3c-docs

    The IDL attribute complete must return true if any of the following conditions is true:

    • The src attribute is omitted.
    • The src attribute's value is the empty string.
    • The final task that is queued by the networking task source once the resource has been fetched has been queued, but has not yet been run, and the img element is not in the broken state.
    • The img element is completely available.

    Sounds like the result is correct. Assuming the inital image is cached, then the image already has been fetched.
    It doesn't have any effect to the complete-property when you change the src(queue another task)

    I played around a little bit and it looks as if you get the expected result when you remove the src-attribute before setting the new src. Demo: http://jsfiddle.net/doktormolle/UNEF7/

    Explanation: When no src-attribute is present the state of the image turns to "broken"(the 3rd condition will not match anymore) and it will not be complete before the new ressource has been loaded.

提交回复
热议问题