我想要一个5个字符的字符串,由从集合[a-zA-Z0-9]中随机选取的字符组成。
用JavaScript实现这一点的最佳方法是什么?
我想要一个5个字符的字符串,由从集合[a-zA-Z0-9]中随机选取的字符组成。
用JavaScript实现这一点的最佳方法是什么?
当前回答
为后代发布ES6兼容版本。如果这是多次调用,请确保将.length值存储到常量变量中。
// USAGE:
// RandomString(5);
// RandomString(5, 'all');
// RandomString(5, 'characters', '0123456789');
const RandomString = (length, style = 'frictionless', characters = '') => {
const Styles = {
'all': allCharacters,
'frictionless': frictionless,
'characters': provided
}
let result = '';
const allCharacters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
const frictionless = 'ABCDEFGHJKMNPQRSTUVWXYZabcdefghjkmnpqrstuvwxyz23456789';
const provided = characters;
const generate = (set) => {
return set.charAt(Math.floor(Math.random() * set.length));
};
for ( let i = 0; i < length; i++ ) {
switch(Styles[style]) {
case Styles.all:
result += generate(allCharacters);
break;
case Styles.frictionless:
result += generate(frictionless);
break;
case Styles.characters:
result += generate(provided);
break;
}
}
return result;
}
export default RandomString;
其他回答
function randomString (strLength, charSet) {
var result = [];
strLength = strLength || 5;
charSet = charSet || 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
while (strLength--) { // (note, fixed typo)
result.push(charSet.charAt(Math.floor(Math.random() * charSet.length)));
}
return result.join('');
}
这是最干净的了。它也很快,http://jsperf.com/ay-random-string.
您可以使用Web Crypto的API:
console.log(self.crypto.getRandomValues(新Uint32Array(1))[0])
(此处为原始答案)
如果可以使用库,Chance.js可能会有所帮助:http://chancejs.com/#string
快速和改进的算法。不保证统一(见注释)。
function getRandomId(length) {
if (!length) {
return '';
}
const possible =
'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
let array;
if ('Uint8Array' in self && 'crypto' in self && length <= 65536) {
array = new Uint8Array(length);
self.crypto.getRandomValues(array);
} else {
array = new Array(length);
for (let i = 0; i < length; i++) {
array[i] = Math.floor(Math.random() * 62);
}
}
let result = '';
for (let i = 0; i < length; i++) {
result += possible.charAt(array[i] % 62);
}
return result;
}
这是肯定的
<script language="javascript" type="text/javascript">
function randomString() {
var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz";
var string_length = 8;
var randomstring = '';
for (var i=0; i<string_length; i++) {
var rnum = Math.floor(Math.random() * chars.length);
randomstring += chars.substring(rnum,rnum+1);
}
document.randform.randomfield.value = randomstring;
}
</script>