JS宏 怎么申请全局的数组变量？这个代码提示函数外不能赋值操作

var MAX_COL = 30;

var new_bom_number;

var old_bom_number;

var del_list = [];

//add_list = [];

//modify_list_new = [];

//modify_list_old = [];

function compBOM(){

old_bom_number = 0;new_bom_number = 0;del_list = [];

del_list[0] = 1;

del_list[1] = 2;

Console.log("del_list0:"+del_list[0]);

bomlistCount();

Console.log("新BOM:"+new_bom_number);

Console.log("旧BOM:"+old_bom_number);

return;

}