var total = 6480; //总数
var curN = 4480; //当前值
function show()
{
var box = document.getElementById("box");
var o = document.getElementById("bar");
o.style.width = ((curN / total) * 200) + 'px'; //200是外框的宽度
}
show();
取反：
var total = 6480; //总数
var curN = 6400; //当前值
var baseNub = total - curN;
function show()
{
var box = document.getElementById("box");
var o = document.getElementById("bar");
o.style.width = ((baseNub / total) * 200) + 'px'; //200是外框的宽度
}
show();
