Basically async and defer are attributes that can be used by <script> to improve page speed by decreasing loading lag.<\/span><\/p>\n <\/p>\n We add this attribute to script tag in HTML to control script loading and executing.<\/span><\/p>\n async :<\/strong> 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.<\/span><\/p>\n <\/p>\n defer :<\/strong> 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.<\/span><\/p>\n <\/p>\n async :<\/strong> The script can run before DOM has fully loaded and it doesn\u2019t execute in order. Suitable for scripts which do not perform DOM manipulation.<\/span><\/p>\n <\/p>\n defer : <\/strong>The script always executes in order in which they appear in HTML. Suitable for scripts which perform DOM manipulation.<\/span><\/p>\n <\/p>\n Quick Visualization<\/span><\/p>\n <\/p>\n 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<\/p>\n","protected":false},"author":51,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[333,172],"tags":[330],"class_list":["post-4981","post","type-post","status-publish","format-standard","category-asynchronous-javascript","category-javascript","tag-javascript"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/4981","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/users\/51"}],"replies":[{"embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/comments?post=4981"}],"version-history":[{"count":1,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/4981\/revisions"}],"predecessor-version":[{"id":5005,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/4981\/revisions\/5005"}],"wp:attachment":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/media?parent=4981"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/categories?post=4981"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/tags?post=4981"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Why? (do we use)<\/span><\/h1>\n
<\/h1>\n
How? (it works)<\/span><\/h1>\n
When? (to use)<\/span><\/h1>\n
![](\"https:\/\/namastedev.com\/blog\/wp-content\/uploads\/2024\/09\/nishi_surti_Blog.webp\")
<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"