The forgotten 90s JavaScript... I wonder who created this terrible API in the first place: window.open("about:blank", null, "height=500,width=500,top

The forgotten 90s JavaScript... I wonder who created this terrible API in the first place: window.open("about:blank", null, "height=500,width=500,top=100,left=100"); i.e. this argument list as string. It looks like a workaround for language limitations, such as passing an object/dictionary. Why was it done with the string in the 90s?