env undefine

[sunqi]

i find the composer in my website can't suit the screen..
so i just check out the js code and try to add alert(env) in
if (percentage) {
if ( env === 'md' || env === 'lg') {
postContainer.css('height', Math.floor($(window).height() * percentage) + 'px');
}
}
what i get is undefine. seems that the function findBootstrapEnvironment() doesn't work
who can tell me what is my lack