How does js implement a drop-down box change, and the image next to it also changes _ image effects

It is generally used to select an Avatar or select a desired profile.

<Select id = "s1" onchange = 'document. getElementById ("pic "). src = this. value'> <option value = "/upload/20080918164946929.gif"> biggrin </option> <option value ="/upload/20080918164946913.gif"> confused </option> <option value = "/upload /20080918164946995.gif"> cool </option> <option value = "/upload/snapshot> eek </option> <option value ="/upload/20080918164946725.gif"> frown </option> <option> value = "/upload/20080918164946792.gif"> han </option> <option value ="/upload/20080918164946356.gif"> mad </option> <option value = "/upload/expires> redface </option> <option value = "/upload> rolleyes </option> <option value ="/upload/20080918164946854.gif"> smile </option> <option value = "/upload /20080918164947307.gif"> tongue </option> <option value = "/upload/20080918164947238.gif"> wink </option> </select>
[Ctrl + A select all Note: If you need to introduce external Js, You need to refresh it to execute]