img rollover problem, help please

Hello, first sorry, i not speak english very well

I am trying create a simple img rollover

like this:

<img src=”url_pic1″ onmouseover=”this.src=’url_pic2′” onmouseout=”this.src=’url_pic1′” alt=”” />

when change tab from text to visual, remove script code and return this:

<img src=”url_pic1″ alt=”” />

Any way to add scripts to tags?

Thanks^^

pd:
WordPress v4.1
I try with tiny advance editor but same problem