使用angularjs在上传输入类型=文件之前验证文件大小

I have an input type=file element in my form. I want to create a custom directive for checking the file size as soon as I select a file using the input element. I know how to create a create a custom directive, but is there any way in angularjs to determine the file size of the selected element. No Jquery is to be used.I have an input type=file element in my form. I