function posItem(arr, key) {
    	var reg  = new RegExp('^' + encode(key) + '=[^,;]*,expire='),
    	    pos  = -1, i = 0, j = arr.length;

		for (; i < j; i++) {
			if (reg.exec(arr[i])) {
				pos = i;
				break;
			}
		}
		return pos;
    }
get position of data has the key in array
@param  {Array}     arr where data group
@param  {String}    key key The key of the store
@return {Number}    key's position, without is -1