AnApprentice - 6 months ago 37
Javascript Question

# JavaScript, Generate a Random Number that is 9 numbers in length

I'm looking for an efficient, elegant way to generate a JavaScript variable that is 9 digits in length:

Example: 323760488

Answer Source

You could generate 9 random digits and concatenate them all together.

Or, you could call `random()` and multiply the result by 1000000000:

``````Math.floor(Math.random() * 1000000000);
``````

Since `Math.random()` generates a random double precision number between 0 and 1, you will have enough digits of precision to still have randomness in your least significant place.

If you want to ensure that your number starts with a nonzero digit, try:

``````Math.floor(100000000 + Math.random() * 900000000);
``````

Or pad with zeros:

``````function LeftPadWithZeros(number, length)
{
var str = '' + number;
while (str.length < length) {
str = '0' + str;
}

return str;
}
``````

Or pad using this inline 'trick'.

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