如何在下载之前发现文件大小
许多次，当我们下载文件时，我们不是肯定的大约文件的大小。 只有当下载开始时，我们来知道文件大小。 得到文件大小 是a 自由Internet Explorer添加物 那允许您在下载之前发现文件的大小它。
一次安装添加物，它将增加项目到用鼠标右键单击菜单。 您需要的所有是用鼠标右键单击在下载链接，并且精选得到文件大小。
Thats a neat add-on for IE but I guess we should get more if we search for it. I believe MS is not marketing IE like Firefox is doing.
I wonder how it predicts download time..
When sending header and getting response, it may be able to time response but without downloading the file (or take a predefined speed rate), it is impossible to measure download time, or it could be pretty inaccurate.
For FF user, download statusbar is an option, but it shows information in the status bar while downloading the file.
Well most of us use some kind of Download Manager, but getting file size before starting downloading file looks difficult, No workaround
for FF users 
Search for Firefox addon with name “get file size firefox” in google. I am sure you will found something useful.
Good to see some add on for IE