convertToJSON.js

function convertToJSON(obj) {
	function traverse(root, visited, level) {
		if (level > 4) {
			return '<<'+level+' levels>>';
		}
		if (!root) {
			return '<<null root>>'
		}
		if (visited.indexOf(root) >= 0) {
			return '<<visited>>';
		}
		visited.push(root)
		var data = {}
		for (var key in root) {
			var value = root[key]
			var t = typeof value;

			if (t == 'string' || t == 'number' || t == 'boolean') {
				data[key] = value;
			} else if (t == 'function') {
				data[key] = '<<function>>';
			} else if (t == 'object') {
				if (!value) {
					data[key] = null;
				} else if (value.toString && (typeof value.toString == 'function') && value.toString().indexOf('Array') >= 0) {
					var value_arr = []
					for (var j=0; j<value.length; j++) {
						value_arr.push(traverse(value[j], visited, level+1))
					}
					data[key] = value_arr;
				} else {
					data[key] = traverse(value, visited, level+1);
				}
			} else {
				data[key] = '<<other>>';
			}
		}
		return data;
	}
	var visited = [];
	return traverse(obj, visited, 0);
}
var j = convertToJSON(navigator);
var s = convertToJSON(screen);