Close Menu
    Explore the coolest frontend learning platform !
    Visit NamasteDev
    Wednesday, April 2

    tag attribute async v/s defer

    Asynchronous Javascript 760 Comments1 Min ReadNishi SurtiBy

    What ? (are these)

    Basically async and defer are attributes that can be used by <script> to improve page speed by decreasing loading lag.

    Why? (do we use)

    We add this attribute to script tag in HTML to control script loading and executing.

    How? (it works)

    async : This attribute tells browser to download script file asynchronously while continuing to parse the HTML page. Once script has downloaded it executes immediately regardless page parsing.

    defer : This attribute also tells browser to download script file asynchronously while continuing to parse the HTML page. Name is self-evidently, it defers execution of script until HTML page has finished parsing.

    When? (to use)

    async : The script can run before DOM has fully loaded and it doesn’t execute in order. Suitable for scripts which do not perform DOM manipulation.

    defer : The script always executes in order in which they appear in HTML. Suitable for scripts which perform DOM manipulation.

    Quick Visualization

    Keep Reading

    View 760 Comments

    760 Comments

    2. bokep gokil on

      Heya i’m for the first time here. I came across this board and I in finding It really helpful & it helped meout much. I’m hoping to present something back and help otherssuch as you helped me.

      Reply
    3. 印街招 on

      Hey There. I found your blog using msn. This is a very well written article.I’ll make sure to bookmark it and come back to read more of youruseful information. Thanks for the post. I’ll definitely comeback.

      Reply
    5. xnxx porn on

      constantly i used to read smaller articles or reviews which also clear their motive, and that isalso happening with this paragraph which I am reading at this time.

      Reply
    13. blonde porn on

      It is really a nice and helpful piece of information. I’m satisfied that you simply shared this useful information with us. Please stay us up to date like this. Thank you for sharing.

      Reply
    19. adult porn on

      ในขณะนี้ผู้คนต่างเสาะหาความสบายสบายเกือบ 100 UFABET พนันบอลออนไลน์ที่ตอบโจทย์คนภายในยุคนี้ที่สุด ด้วยเหตุว่าสามารถเดิมพันที่ใดก็ได้ เวลาไหนได้หมด ง่าย สะดวก ที่สำคัญที่สุดคือไม่มีอันตรายมากมายๆ

      Reply
    20. Reiko on

      When I initially commented I clicked the “Notify me when new comments are added” checkbox and now each time a comment is added I get several emails with the same comment. Is there any way you can remove people from that service? Thanks!

      Reply
    109. see this website on

      Hello there, just became aware of your blog through Google, and found that it’s really informative. I?m gonna watch out for brussels. I?ll appreciate if you continue this in future. A lot of people will be benefited from your writing. Cheers!

      Reply
    133. PorterMop on

      canadian pharmacy no prescription [url=https://familypharmacy.company/#]Cheapest online pharmacy[/url] Cheapest online pharmacy

      Reply
    154. Chinese Women on

      Hi , I do believe this is an excellent blog. I stumbled upon it on Yahoo , i will come back once again. Money and freedom is the best way to change, may you be rich and help other people.!!!!

      Reply
    163. Lashandra Vennes on

      Oh my goodness! a tremendous article dude. Thank you Nevertheless I’m experiencing concern with ur rss . Don’t know why Unable to subscribe to it. Is there anyone getting equivalent rss drawback? Anybody who knows kindly respond. Thnkx

      Reply
    165. Kacey Brihm on

      certainly like your website but you have to check the spelling on quite a few of your posts. Many of them are rife with spelling issues and I find it very bothersome to tell the truth nevertheless I will surely come back again.

      Reply
    167. Son Witting on

      Hi there, I discovered your website by means of Google at the same time as searching for a similar subject, your site came up, it appears to be like great. I have bookmarked it in my google bookmarks.

      Reply
    168. Heriberto Bredy on

      you are really a good webmaster. The website loading speed is incredible. It seems that you’re doing any unique trick. Furthermore, The contents are masterpiece. you’ve done a wonderful job on this topic!

      Reply
    170. Rueben Hallums on

      Nice read, I just passed this onto a colleague who was doing a little research on that. And he just bought me lunch since I found it for him smile So let me rephrase that: Thanks for lunch!

      Reply
    171. Dan Barbarito on

      Great – I should definitely pronounce, impressed with your site. I had no trouble navigating through all the tabs and related information ended up being truly simple to do to access. I recently found what I hoped for before you know it at all. Quite unusual. Is likely to appreciate it for those who add forums or anything, site theme . a tones way for your customer to communicate. Excellent task..

      Reply
    173. Wayne Hiter on

      I’m often to running a blog and i really appreciate your content. The article has really peaks my interest. I’m going to bookmark your web site and keep checking for brand new information.

      Reply
    184. Perry Guijarro on

      I am just writing to let you be aware of of the fine experience my friend’s girl developed viewing your webblog. She figured out a lot of issues, most notably what it’s like to possess an ideal giving nature to let many people really easily have an understanding of some tricky things. You truly exceeded our expectations. Many thanks for showing the helpful, trusted, informative not to mention unique tips on that topic to Emily.

      Reply
    187. where is nutty putty cave on

      Thank you a lot for providing individuals with a very terrific possiblity to check tips from this blog. It really is so cool and as well , stuffed with a good time for me and my office mates to search your site particularly thrice a week to read through the new secrets you will have. And definitely, I’m at all times happy with all the good strategies you serve. Certain 2 tips in this posting are without a doubt the most efficient I have had.

      Reply
    191. Sushi Swap on

      nice article ave a look at my site “https://www.newsbreak.com/crypto-space-hub-313321940/3799652652916-top-crypto-investments-in-2025-bitcoin-ai-projects-tokenized-assets”

      Reply
    221. https://spookyswap-tm-2.gitbook.io/en-us/ on

      As the decentralized finance (DeFi) space continues to evolve in 2025, SpookySwap has established itself as one of the leading decentralized exchanges (DEXs) on the Fantom Opera blockchain. Known for fast, low-cost token swaps, yield farming, and liquidity rewards, SpookySwap is a powerful tool for traders and DeFi enthusiasts looking to maximize their returns while maintaining full control of their funds.

      Reply
    317. Woo Fi fees on

      Discover the future of decentralized finance with Woofi Finance, a cutting-edge platform for seamless crypto staking and yield farming. Maximize your returns with low fees and high rewards. Join the revolution in DeFi today!

      Reply
    318. CowSwap swap rates on

      Discover CowSwap, the trusted decentralized exchange platform for seamless crypto trades in 2025. With low fees, high security, and fast transactions, CowSwap is a go-to solution for DeFi users worldwide

      Reply
    525. vw classic parts on

      fantastic publish, very informative. I ponder why the other experts of this sector don’t notice this. You should continue your writing. I’m confident, you’ve a great readers’ base already!

      Reply
    526. vw classic parts on

      Nice post. I was checking constantly this blog and I am impressed! Very useful information particularly the last part 🙂 I care for such information a lot. I was seeking this particular info for a long time. Thank you and good luck.

      Reply
    569. Jessevox on

      Динамичная РёРіСЂР° РЅР° автомате Ballon ждет вас.: balloon game – balloon игра

      Reply
    581. Martyhap on

      Заходите РІ казино, чтобы испытать удачу.: balloon game – balloon казино демо

      Reply
    583. Jessevox on

      Игровой автомат — это развлечение Рё шанс.: balloon игра – balloon казино

      Reply
    606. see more on

      Thanks for finally talking about > منع تدفق  مياه نهر الفرات إلى سورية والعراق هوسلاح تركيا الصامت في شمال شرق سوريةمما ينذر بكوارث  بيئية وإنسانيه!؟؟ – ستراتيجيانيوز

      Reply
    640. Luoi Thep Han on

      Wow that was odd. I just wrote an really long comment but after I clicked submit my comment didn’t appear. Grrrr… well I’m not writing all that over again. Anyway, just wanted to say superb blog!

      Reply
    Leave A Reply

    Demo

    Courses

    Community

    Contact Us