As far as I am aware, SimpleDateFormat is not available in standard JavaScript.
You may have been looking at a Java date reference or a JavaScript library that provides a function SimpleDateFormat.
If all you want is to display the time in 12 hour format, the easiest answer may be to write a little function to do that, based on what you can find at
http://www.w3schools.com/jsref/jsref_obj_date.asp
Or you could find a pre-written function somewhere like
http://stackoverflow.com/questions/8888491/how-do-you-display-javascript-datetime-in-12-hour-am-pm-format
new Date().toString("hh:mm")