‘Higher-order functions’ is a fancy term for functions that take other functions as arguments or that return functions. Very powerful!

Forms are an essential part of HTML pages, and developers typically use JavaScript to elaborate on how they function.

So, I have an SVG graphic embedded in an html page.within the svg are some mouseover events that do some re-drawing stuff.Now I want the containing page to also make some updates as a result of ...

The JavaScript in Listing B handles this task. The function is called when the user submits the form. This may be handled with an HTML button’s onSubmit event: ...