It is not easy to construct large Javascript apps. This is particularly true for larger front-end projects. Setup is time-consuming due to the large number of tools that must be combined to build an environment for such a project. The most significant flaw or disadvantage of JavaScript is that the code is continually visible to everyone with internet access. The JavaScript Document Object Model (DOM) is slow and can never render as rapidly as HTML, regardless of how fast JavaScript interprets. If there is an issue with JavaScript, the entire website may stop operating. Browsers are highly tolerant of JavaScript errors. JavaScript is interpreted differently by various browsers. Cross-browser code becomes a little more challenging to comprehend and develop due to this.