How to split string between two separators in javascript?

Using split between specific characters without losing any characters is not possible with JavaScript, because you would need a lookbehind for that (which is not supported). But since you seem to want the texts inside the parentheses, instead of splitting you could just match the longest-possible string not containing parentheses:

myArray = "(text1)(text2)(text3)".match(/[^()]+/g)

.split(/[()]+/).filter(function(e) { return e; });

See this demo.