实现算法以找到最近的地方

I want to create a simple web app to find the nearest place from a given position. What I want do is: taken my position through geolocation function in Google maps, find the nearest place in a map. A list of places to be considered is saved in a MySQL db. Every record has two fields: latitude and longitude. After parsing these two values I need to calculate the distance and obtain the nearest place. How can I use JavaScript and PHP to accomplish this?I want to create a simple web app to find the n