I was searching through the internet for a method of changing Safari’s integrated search box and came across this little gem on alexking.org. If you change a standard:

<input type="text" />

field to a “search” box like so:

<input type="search" />

In Safari, it is magically transformed from a standard input field to a “search box”. It can also have added functionality like remembering previous searches with an extra attribute:

<input type="search" results="5" />

Here is a screenshot:

 Safari