Jscript is a language that has been set apart from JavaScrip to own its ECMA Script language. Java Script is a freshly developed language and has to be cautiously laid down as per the pertaining rules to get the best result possible.
Another main difference between the two is the ability of JScript to access and open Internet Explorer. Java Script will not be able to do this. It is best that you know the difference between the two so you can decide which one will be more ideal to use.