Video: Script async defer yog dab tsi?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Qhov txawv ntawm async thiab ncua centers nyob ib ncig ntawm thaum lub tsab ntawv raug tua. Txhua async tsab ntawv executes ntawm thawj lub sijhawm tom qab nws ua tiav kev rub tawm thiab ua ntej lub qhov rais load tshwm sim. Raws li qhov ncua scripts , ntawm qhov tod tes, tau lees tias yuav raug tua nyob rau hauv qhov kev txiav txim lawv tshwm sim hauv nplooj ntawv.
Kuj nug, qhov twg zoo dua async lossis ncua?
DEFER ib txwm ua rau cov ntawv ua tiav tshwm sim tib lub sijhawm los yog tom qab ntawd ASYNC . Yog li ntawd, nws yog zoo dua siv DEFER yog li ntawd lawv qhov kev tua tshwm sim sab nraum lub sijhawm ua haujlwm tseem ceeb. DEFER scripts yeej tsis thaiv synchronous scripts, thaum ASYNC scripts yuav nyob ntawm seb lawv download tau sai npaum li cas.
Tsis tas li ntawd, script defer txhais li cas? Txhais thiab siv The ncua tus cwj pwm yog ib tug boolean attribute. Thaum tam sim no, nws qhia tias tus script yog raug tua thaum nplooj ntawv tiav parsing. Lus Cim: Cov ncua tus cwj pwm yog tsuas yog rau sab nraud ntawv (yuav tsum tsuas yog siv yog src attribute yog tam sim no).
Hais txog qhov no, tsab ntawv async txhais li cas?
Cov async tus cwj pwm yog ib tug boolean attribute. Thaum tam sim no, nws qhia tias tus tsab ntawv yuav raug tua asynchronously sai li sai tau yog muaj. Yog tsis yog async los yog defer yog tam sim no: Cov script yog nqa thiab tua tam sim ntawd, ua ntej browser txuas ntxiv parsing nplooj.
Kuv puas tuaj yeem siv tsab ntawv ncua?
Hauv kev xyaum, ncua yog siv rau ntawv uas xav tau tag nrho DOM thiab / lossis lawv cov txheeb ze kev txiav txim yog qhov tseem ceeb. Thiab async yog siv rau kev ywj pheej ntawv , zoo li cov txee lossis kev tshaj tawm. Thiab lawv cov txheeb ze kev txiav txim ua tsis muaj teeb meem.
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