If you just want to quickly try out some SVG in your browser and not mess around with saving and loading files, jsFiddle is a great option.
Just use the following code as a template:
<svg xmlns="http://www.w3.org/2000/svg">
<path d="your path data here"></path>
</svg>
I created a sample to work from here.
jsFiddle also supports frameworks such as D3, PaperJs and Raphael from a dropdown on the left-hand side.