生成随机编码

function randomCode(length, isNumber) {  
	let result = '';  
	const characters1 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
	const characters2 = '0123456789';
	const charactersLength = isNumber ? characters2.length : characters1.length;  
	for (let i = 0; i < length; i++) {  
		if (isNumber) {  
			result += characters2.charAt(Math.floor(Math.random() * charactersLength));  
		} else {  
			result += characters1.charAt(Math.floor(Math.random() * charactersLength));  
		}  
	}  
	return result;  
}