试试这个:

$("#element").text().length;

它在使用中的例子

var x = 1234567;

x.toString().length;

这个过程也适用于浮点数和指数数。

你应该使用最简单的字符串(stringLength)，可读性总是胜过速度。但如果你关心速度，下面有一些。

三种不同的方法，速度各不相同。

// 34ms
let weissteinLength = function(n) { 
    return (Math.log(Math.abs(n)+1) * 0.43429448190325176 | 0) + 1;
}

// 350ms
let stringLength = function(n) {
    return n.toString().length;
}

// 58ms
let mathLength = function(n) {
    return Math.ceil(Math.log(n + 1) / Math.LN10);
}

// Simple tests below if you care about performance.

let iterations = 1000000;
let maxSize = 10000;

// ------ Weisstein length.

console.log("Starting weissteinLength length.");
let startTime = Date.now();

for (let index = 0; index < iterations; index++) {
    weissteinLength(Math.random() * maxSize);
}

console.log("Ended weissteinLength length. Took : " + (Date.now() - startTime ) + "ms");


// ------- String length slowest.

console.log("Starting string length.");
startTime = Date.now();

for (let index = 0; index < iterations; index++) {
    stringLength(Math.random() * maxSize);
}

console.log("Ended string length. Took : " + (Date.now() - startTime ) + "ms");


// ------- Math length.

console.log("Starting math length.");
startTime = Date.now();

for (let index = 0; index < iterations; index++) {
    mathLength(Math.random() * maxSize);
}

也可以使用模板字符串:

const num = 123456
`${num}`.length // 6

是的，你需要转换为字符串，以找到长度。例如

var x=100;// type of x is number
var x=100+"";// now the type of x is string
document.write(x.length);//which would output 3.

为了获得任何由小数部分和小数部分分开的数字的相关位数(如果前导小数部分为0，则整个部分的长度为0)，我使用:

function getNumberLength(x) {
  let numberText = x.toString();
  let exp = 0;
  if (numberText.includes('e')) {
    const [coefficient, base] = numberText.split('e');
    exp = parseInt(base, 10);
    numberText = coefficient;
  }
  const [whole, decimal] = numberText.split('.');
  const wholeLength = whole === '0' ? 0 : whole.length;
  const decimalLength = decimal ? decimal.length : 0;
  return {
    whole: wholeLength > -exp ? wholeLength + exp : 0,
    decimal: decimalLength > exp ? decimalLength - exp : 0,
  };
}