張心姿w3schools物件object亂數random進位ceil捨去floor

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教學影片343,344,345

亂數,無條件進位ceil,捨去floor,四捨五入round

輸入數字N

Math.random()亂數Method產生0(含)到N(不含)

Math.floor()無條件捨去Method

Math.ceil()進位Method

Math.round()四捨Method

以上程式碼在撰寫模式貼上

<h1>劉天王JavaScript語言Math數學方法(內建函數)</h1>

<h2>Math.random()亂數Method產生0(含)到7(不含)</h2>

<p id="demo"></p>

<h2>Math.floor()無條件捨去Method</h2>

<p id="demo1"></p>

<h2>Math.ceil()進位Method</h2>

<p id="demo2"></p>

<h2>Math.round()四捨Method</h2>

<p id="demo3"></p>

<script>

let x = Math.random()*7;

document.getElementById("demo").innerHTML = x;

document.getElementById("demo1").innerHTML = Math.floor(x);

document.getElementById("demo2").innerHTML = Math.ceil(x);

document.getElementById("demo3").innerHTML = Math.round(x);

</script>

新增的重要指令

輸入數字N<input value=7 type="number" id="n" min="1" max="9"/>

<button onclick="abc()">張心姿執行</button>

script 程式部分

function abc(){

let n = document.getElementById("n").value;

let x = Math.random()*n;

...}