Mouse Scroll wheell is not worked when mouse over the i-fame of the page

In my website there is a i-frame in a area of the page. All the page the mouse scroll is working perfectly but when the mouse over the i-fame the mouse scroll is not worked. This problem is shown in chrome only but the Firefox bowers is worked properly. I can not find the solution yet.Please help me.i am feed up to find the solution.please help.