There is no alternative to var before ES6, so of course your only option is to use it. If you use any of the various compilers that introduce let and const, it

There is no alternative to var before ES6, so of course your only option is to use it. If you use any of the various compilers that introduce let and const, it is recommended to use them over var. These compilers basically just check, at compile time, those variables satisfy the correct behaviors of let and const and just converts them to var for ES5 and below.