先端基本JSフロー制御文(4)

15507 ワード

forサイクル

<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>fortitle>
    <style>
     body{text-align:left;}
    style>
head>
<body>
   <script>
     // 1-100 101   1 2 3 4
     //          //            
     for(var i=1;i<=100;i++){
        document.write(i+'
'
); // 1 2 3 100 } // 99 97 95 ...3 1 for(var m=99;m>=1;m-=2){ console.log(m); // 99 97 3 1 } //alert(m); // -1
script> body> html>
ループネスト
 for(var i=1;i<=9;i++){       
                       // i=1; j<=1;  i=2;
      for(var j=1;j<=i;j++){
         document.write(j+'*'+i+'='+j*i+'  '); 
               // 1*1=1  1*1=1 2*2=4
          }
          document.write('
'
); }
分岐文

<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Documenttitle>
head>
<body>
    <script>
       /*var age=35;
       if(age<18){
          alert("      ");
       }
       var age=prompt("       ");
       /*if(age<18){
          alert("      ");
       }else{
          alert("    ,         ");
       }
       if(age.length!=6){
          alert("   6     ");
       }else{
          if(isNaN(age)){
            alert("     6   ");
          }else{
            alert("      ");
          }
       }*/
       var score=prompt("     ");
       var result="";
       if(isNaN(score)){
          alert("       ");
       }else{
          if(score<0 || score>100){
             alert("        ");
          }else{
             switch(parseInt(score/10)){
                case 0:
                case 1:
                case 2:
                case 3:
                case 4:
                case 5:
                result="   ";
                break;
                case 6:
                result="  ";
                break;
                case 7:
                result="  ";
                break;
                case 8:
                result=" ";
                break;
                case 9:
                result=" ";
                break;
                default:
                result="  "
             }
             alert("     :"+result);
          }
       }
    script>
body>
html>
while

<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>whiletitle>
head>
<body>
    <script>
       var i=1;
       while(i<=100){
          document.write(i+'
'
); // 1 2 100 i+=1; // i++ } //1 - 10 /* var j=18; do{ if(j%2==0){ console.log(j); } j++; }while(j<=10); */ // 1+2+3+4+...100=? // sum=0+1=1 // sum=0+1+2 // sum=0+1+2+3 // sum=0+1+2+3+4 var sum=0; // sum var n=1; while(n<=100){ sum+=n; // sum=sum+n; // sum=0+1; sum=0+1+2+3+100 n++; } console.log(sum);
script> body> html>
スイッチ

<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Documenttitle>
head>
<body>
    <script>
       for(var i=0,col="";i<=100;i++){
          switch(i%4){
             case 0:
             col="red";
             break;
             case 1:
             col="green";
             break;
             case 2:
             col="blue";
             break;
             default:
             col="orange";
          }
          document.write(''">'+i+'
'
); }
script> body> html>
contine&break

<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>break continuetitle>
head>
<body>
    <script>
       var num=0;
       for(var i=1;i<10;i++){
          //   i 5   ,  
          if(i%5==0){
             break;
          }
          num++;   // i=1,num=1;i=2,num=2;i=3,num=3,i=4,num=4,i=6,num=5
       }
       //console.log(num);
       for(var s=0,j=1;j<=10;j++){
          if(j%5==0){
             continue;
          } 
          s+=j;
          // j=1,s=1;j=2,s=3;j=3,s=6;j=4,s=10,j=5,s=10;j=6,s=16,j=7,s=23;j=8,s=31;j=9,s=40,j=10
       }
       //console.log(s);
       //     0-50   20 30   5   
       for(var n=0;n<=50;n+=5){
          if(n==20 || n==30){
             continue;
          }
          console.log(n);
       }
    script>
body>
html>