> For the complete documentation index, see [llms.txt](https://javascriptuse.gitbook.io/javascript/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://javascriptuse.gitbook.io/javascript/click-lan-dau-su-event.preventdefault-lau-sau-not-event.preventdefault.md). # Click lần đầu sử event.preventDefault(); lầu sau not event.preventDefault(); ![](https://2494213435-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LYjAG13rAPdbArSfRyB%2F-Lx4RUFxeI2feuy3dHh4%2F-Lx4RrLaHTGTLYnpZaD1%2FClick%20One%2C%20Click%20More.png?alt=media\&token=63cf71db-bab7-4f05-8e1b-44b978469a33) ``` Document ```