as it always evolved, javascript is the best... you can use many framework available by free to help you out with the coding.
I have never Heard about VB Script anymore So For me Java Script is The best Scripting Language Ever.
I go with Java Script as now most of browser support js and also after java script you can learn jquery which is best than other.
The better question would be, "Which is scripting language is better for task x?" Asking a broad question will only bring out the language zealots, purporting that "their" language is better than all others. However, examine the task at hand. Which language is going to get you to the required goal with the cleanest and shortest effort? Each language has its pros and cons. The zen developer will not focus on a single tool, but rather be open-minded or familiar with many tools, each having it's own niche or suitability to a particular task.