JS學習記錄（補充二）

最後更新：2017-08-03 來源：互聯網

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標籤：技術 write style tle har com ... tin prompt

迴圈變數
<html lang="en"><head>    <meta charset="UTF-8">    <title>迴圈變數</title></head><body><script>    /*1+2+3+...10*/    var i = 1;                  //迴圈變數的定義    var sum = 0;    while (i <= 10) {           //迴圈變數的判斷        if (i % 2 == 0) {            sum = sum + i;      //迴圈變數的更新        }        i++;    }    alert(sum);</script></body></html>

結果圖：

求出100到1000的水仙花數


<html lang="en"><head>    <meta charset="UTF-8">    <title>求出100到1000的水仙花數</title></head><body><script>    var i = 100;    while (i <= 999) {        var i1 = i % 10;        var i2 = parseInt(i / 10 % 10);        var i3 = parseInt(i / 100);        if (i == Math.pow(i1, 3) + Math.pow(i2, 3) + Math.pow(i3, 3)) {            alert(i);        }        i++;    }</script></body></html>

結果圖：

累加求和


<html lang="en"><head>    <meta charset="UTF-8">    <title>累加求和</title></head><body><script>    var sum = 0;    var num = parseInt(prompt("輸入您要累加的數"));    while (num != -1){        sum += num;        num = parseInt(prompt("請輸入您要累加的數"));    }    alert(sum);</script></body></html>

結果圖：

例：輸入5和3得到8

do-while語句
<html lang="en"><head>    <meta charset="UTF-8">    <title>do-while</title></head><body><script>    var i = 1;              //迴圈變數的初始化    var sum = 0;    do {        sum += i;        i++;                //迴圈變數的更新    } while (i <= 10);      //迴圈變數的判斷    alert(sum);</script></body></html>

結果圖：

迴圈的嵌套



<html lang="en"><head>    <meta charset="UTF-8">    <title>迴圈的嵌套</title></head><body><script>    var i = 1;    var sum1 = 0;    while (i <= 5) {        var j = 1;        while (j <= i) {            sum1 += j;            j++;        }        i++;    }    alert(sum1);</script></body></html>

結果圖：

階乘


 <meta charset="UTF-8">    <title>階乘</title></head><body><script>    var i = 1;    var sum = 0;    while(i <= 5 ){        var j = 1;        var sum1 = 1;        while(j <= i ){            sum1 = sum1*j;            j++;        }        sum += sum1;        i++;    }    alert(sum);</script></body></html>

結果圖：

for迴圈


<html lang="en"><head>    <meta charset="UTF-8">    <title>for迴圈</title></head><body><script>    var sum = 0;    for(var i = 1;i <= 100; i ++){        sum +=i;    }    alert(sum);</script></body></html>

結果圖：

break語句


<html lang="en"><head>    <meta charset="UTF-8">    <title>break語句</title></head><body><script>    var sum = 0;    for (var i = 1;i <= 100;i ++){        sum += i;        if (sum >= 2000){            alert(i+":"+sum);            break;        }    }</script></body></html>

結果圖：

嵌套迴圈的break語句


<html lang="en"><head>    <meta charset="UTF-8">    <title>嵌套迴圈的break語句</title></head><body><!--1+(1+2)+(1+2+3)+(1+2+3+4)+(1+2+3+4+5)--><script>    var sum = 0;    var i = 1;    while (i <= 5){        var j = 1;        while(j <= i ){            if (i == 3){                break;            }            sum += j;            j++;        }        i++;    }    alert(sum);</script></body></html>

結果圖：

九九乘法表


<html lang="en"><head>    <meta charset="UTF-8">    <title>九九乘法表</title></head><body><script>    for(var i=1;i<=9;i++){/*外層迴圈控制顯示的行數*/        for(var j=1;j<=i;j++){            var sum =i*j;            document.write(i+"*"+j+"="+sum+"&nbsp;&nbsp;&nbsp; ");        }document.write("<br>");    }</script></body></html>

結果圖：

continue語句
</title></head>


<html lang="en"><head>    <meta charset="UTF-8">    <title>continue語句</title></head><body><script>    var sum = 0;    for (var i = 1; i <= 100; i++) {        if (i % 3 == 0) {            continue;        }        sum += i;    }    alert(sum);</script></body></html>

結果圖：

JS學習記錄（補充二）

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