How to make or ‘s value different from user’s browser to Chrome Developer Tools in HTML5?

I founded a very interesting trick on a site.A input tag seemed has a normal text value like “My blog title is xxxxx” in browser client window and it can be copied.But when I opened Chrome Developer Tools to review this element, the input tag had no value but a placeholder like “This is a example”.Seemed the owner used some css or javascript tricks to prevent Web crawlers to get input’s value, anybody know how do they achieve this?

<input disabled="" name="Title" type="text" required="" placeholder="This is a example">