easy function like substringBefore in Java ?

easy function like substringBefore in Java ?

Does JQuery provide an easy function like substringBefore in Java ?

My string pattern is "1000 aaa bbb ccc", it always starts with digits, I need to get these digits. In java, we just use substringBefore(str, " "); //before first empty space.

Does JQuery have same function to handle this ?

Thanks.