JS generates 4-digit verification code

Pre knowledge ：
common ASCII The size rule of the code ：0~9<A~Z<a~z

1. Numbers are smaller than letters . Such as “7”<“F”;
2. Numbers 0 More than numbers 9 smaller , And press 0 To 9 The order is increasing . Such as “3"<"8”;
3. Letter A Than letters Z smaller , And press A To Z The order is increasing . Such as “A"<“Z”;
4. The upper case of the same letter is smaller than the lower case 32. Such as “A”<"a”.
   A few common letters ASCII Code size :“A” by 65;“a" by 97;“0” by 48

demand ：
Implement a generated random 4 Function of bit verification code , Contains figures 、 Letter case

Code ：

<script>
// '0' - '9' : 48~57
// 'A' - 'Z' : 65~90
// 'a' - 'z' : 97~122

//  Write a random function , This function can generate numbers in the specified range 
const getRandom = (min,max)=>{
    
	return Math.floor(Math.random()*(max-min+1)) + min
}
const getVerifyCode = ()=>{
    
	let str = ''
	// 3. Cycle four times 
	for(let i=0;i<4;i++){
    
		// 1. Get the corresponding character ASCII Code value 
		const ascii = getRandom(48,122)
		if((ascii>57&&ascii<65)||(ascii>90&&ascii<97)){
    
			i--
			continue
		}
		// 2. adopt ASCII Code value to the corresponding string ：String.fromCharCode(ASCII value )
		const c = String.fromCharCode(ascii)
		// 4. Splice together 
		str += c
	}
	// 5. Return results 
	return str
}
console.log(' The verification code is :', getVerifyCode())
</script>