Not only does jQuery "fix" the bugs and inconsistencies (by detecting them and working around them), it actually makes the DOM API pleasant to use. Querying for elements from the DOM and then manipulating them in various ways used to take dozens of lines of code regardless of how simple the task was. The same can usually be done in jQuery with just one or two lines of code. It's fluent API and focus on usability (for the developer) has changed the way we practice the art of front-end engineering.
After completing this course, you should be proficient in the following: