jsFiddle is the perfect solution; it provides a custom environment (based on user selections) to test (or fiddle with) your JavaScript, HTML, and CSS code right inside your browser. A quick tour ...

[Click on image for larger view.] Figure 1 ... Sciter provides an embeddable, GPU accelerated UI engine for HTML, CSS, and JavaScript interface development in applications written in Delphi, D, Go, C# ...