These create naming collisions and make debugging difficult.
At its core, the book argues that JavaScript was developed too quickly, resulting in a language filled with both brilliance and "terrible parts." Crockford’s thesis is that by intentionally avoiding the problematic features—such as global variables and type coercion—and embracing the elegant ones, developers can write clearer, more maintainable code. The Elegant Core JavaScript: The Good Parts
Since early JavaScript only had function scope (via var ), the book highlights the danger of assuming block-level isolation. Lasting Impact These create naming collisions and make debugging difficult