javascript - 将用户 HTML 输入作为 javascript 函数参数传递

Question

我有这行 JavaScript:

stave.addClef("treble").addTimeSignature("4/4");

根据用户在 HTML 文档中输入的内容，我想将“4/4”更改为“3/4”，或用户输入的任何其他分数。进行这种条件替换的最简单方法是什么？

谢谢， 纳库尔

Answer 1

这是一个允许用户上下切换数字输入的选项:

<input type="number" id="fraction-1"/>
<input type="number" id="fraction-2"/>

Current Signature:
<div id="current-sig"></div>

然后在你的 JavaScript 中...

// Get the select form element
const FRACT_1 = 'fract-1'
const FRACT_2 = 'fract-2'
const fract1 = document.querySelector(`#${FRACT_1}`)
const fract2 = document.querySelector(`#${FRACT_2}`)
const currentSigDiv = document.querySelector('#current-sig')

let currentSignature = '4/4'

const changeSignatureByFraction = ({target}) => {
    if(target.id === FRACT_1)) {
        currentSignature = `${target.value}${currentSignature.substring(1)}`
        stave.addClef("treble").addTimeSignature(currentSignature)
        currentSigDiv.innerHTML = currentSignature
    } else {
        currentSignature = `${currentSignature.slice(0, -1)}${target.value}`
        stave.addClef("treble").addTimeSignature(currentSignature)
        currentSigDiv.innerHTML = currentSignature
    }

}

// Listen for a change event
fract1.addEventListener('change', changeSignatureByFraction)
fract2.addEventListener('change', changeSignatureByFraction)

currentSigDiv.innerHTML = currentSignature