API
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Devjelly






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SNS **
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** URL
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* 404
URL
onerror !
<img
src="http://instarstar.com/some.jpeg"
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alt=" "
/>
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!!
404
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onerror
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, API
URL !
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URL
!
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API !!
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->
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xhr.request(“GET”, url)
= ..
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50
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50 !
2.5 !
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DOM IO .
10 10 , 20 20
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HTTP Method
GET, POST, PUT, DELETE
HEAD .
HEAD HEADER
GET
HEAD
!!!
200
400 !
!
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HEAD GET
100kB * 500
50MB
HEAD 100B * 500
50kB
50MB, 50kB
50000000B
>>>>>>>>>>>>>>>>>>>
50000B
500 50kB !
!
!
MDN ..
…
!
TTFB(Time to first byte)
,
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0. API ,
API
.
1. API
.
2.
IO .
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3. Resource
GET ,
HEAD
.
.
await Promise.all([…])
IO
!
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