Rollover Image Code getting stripped

I found this code in the forums for rollover images. It works, but when the page gets refreshed WordPress is stripping the code like it strips ?

[ Moderator note: code fixed. Please wrap code in the backtick character or use the code button. ]

<a href="https://test.lustreadvisors.com/gold-american-eagle/"><img src="https://test.lustreadvisors.com/wp-content/uploads/2014/07/1oz-gold-american-eagle-obverse.png"
onmouseover="this.src='https://test.lustreadvisors.com/wp-content/uploads/2014/07/1oz-gold-american-eagle-reverse.png'"
onmouseout="this.src='https://test.lustreadvisors.com/wp-content/uploads/2014/07/1oz-gold-american-eagle-obverse.png'" /></a>

I have a child theme of twentytwelve with nothing unusual, any suggestions? I’ve done the plugin deactivation thing.

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