JavaScript — Find key for value in an object

findKey.js

var findKey = function(obj, value)
	{
		var key = null;

		for (var prop in obj)
		{
			if (obj.hasOwnProperty(prop))
			{
				if (obj[prop] === value)
				{
					key = prop;
				}
			}
		}

		return key;
	};