US Visa in Switzerland

Yes you can apply for a visa while you are in Switzerland. As per the official Tourist/Business visa page for US embassy in Switzerland there is nothing to prohibits you from doing so.

However, you will need a list of documents that might not be available with you:

• Current proof of income, tax payments, property or business ownership, or assets, showing sufficient funds to cover all expenses while in the United States.
• Intention to depart the United States upon completion of your travel.
• A letter from your employer detailing your position, salary, how long you have been employed, any authorized vacation, and the business purpose, if any, of your U.S. trip.
• Evidence that you have significant ties to the country to which you intend to return at the end of your stay in the United States (This is generally established by evidence of family, professional, property, employment or other ties and commitments to a country other than the United States.)
• Criminal/court records pertaining to any arrest or conviction anywhere, even if you completed your sentence or were later pardoned.

If you can manage to get all of the above in original copies while you are away from home, then you will be able to apply and might be granted the visa.