Web Basics Learning JS, cycling practice

1. Judging leap years

var i;
for (i=1980;i<=2016;i++)
{
  if (i% 4 = 0 && i%!= 0 | | i% = = 0)
  document.write (i + "");
}

2.99 Multiplication Table

var i, J;
for (i=0;i<10;i++)
{for
  (j=1;j<=i;j++) {
    document.write (i + "*" + j + "=" +i*j);
    document.write ("  ");
  }
document.write ("<br/>");
}

A 3.100-999 Narcissus:

The first method:

var i,a = 0,b =0,c = 0;
for (i = 100;i < 1000;i++) {
   a = parseint (i/100);
   b = parseint (I/10-a *);//b = parseint (i/%100/10);
   c = parseint (i%);
  if (i== (A * a * a + b * b * b + c * c * c))
document.write (i + "");
}

The second method:

for (var i = 1;i < 10;i++) {for
     (var j = 0;j < 10;j++) {for
        (var k=0; k < 10;k++) {
           if (i * + J * 10 + k = i * I * i + J * J * j + K * k * k) {
           document.write (i * + J * + K + "");}}}

4.1+3+5+7.......+99

var i,sum=0;
document.write ("The result of 1+3+5+7.......+99 is:");
for (i = 0;i < 100;i++) {
   if (i% 2!= 0) {
   sum+=i;
   }
}
document.write (sum+ "");

Factorial within 5.100.

var i,sum=1;
document.write ("the factorial result within 100 is:");
for (i = 1;i <= 100;i++) {
   sum*=i;
}
document.write (sum+ "");

6. Print Triangle

for (var i = 0; i < 6; i++) {for
   (var j = 0; J < 5-i; j) {
       document.write ("");
   }
   for (var j = 0; J < i; J +) {
      document.write ("*");
   }
document.write ("<br/>");

}

7. Diamond

for (var i = 0; i < 6; i++) {for
     (var j = 0; J < 5-i; j) {
        document.write ("");
     }
     for (var j = 0; J < 2*i+1; J + +) {
        document.write ("*");
     }
document.write ("<br/>");

}

for (var i = 0; i < 5; i++) {for
    (var j = 0; J < i+1;j++) {
       document.write ("");
    }
    for (var j = 0; J < 2* (4-i)-1 J + +) {
        document.write ("*");
    }
document.write ("<br/>");

}

8. Empty Diamond

for (var i = 0; i < 6; i++) {for
   (var j = 0; J < 5-i; j) {
      document.write ("");
   }
   for (var j = 0; J < 2 * i + 1; j + +) {
     if (j = = 0 | | j = = 2 * i)
        document.write ("*");
     else{
     document.write ("");
     }
   }
document.write ("<br/>");

}

for (var i = 0; i < 5; i++) {for
    (var j = 0; J < i + 1;j++) {
      document.write ("");
    }
    for (var j = 0; J < 2 * (4-i)-1 J + +) {
      if (j = = 0 | | j = = 2 * (4-i)-2)
          document.write ("*");
     else{
         document.write ("");
      }
     }
document.write ("<br/>");
}

9. Judging today is the day of the week

var now = new Date ();
var day = Now.getday ();
var str = ""; Switch (day) {<span style= "White-space:pre" > </span>case 1: <span style= "White-space:pre" > </span
>str = "Monday";
<span style= "White-space:pre" > </span>break; <span style= "White-space:pre" > </span>case 2: <span style= "White-space:pre" > </span>str = "Tuesday
";
<span style= "White-space:pre" > </span>break; <span style= "White-space:pre" > </span>case 3: <span style= "White-space:pre" > </span>str = "Wednesday
";
<span style= "White-space:pre" > </span>break; <span style= "White-space:pre" > </span>case 4: <span style= "White-space:pre" > </span>str = "Thursday
";
<span style= "White-space:pre" > </span>break; <span style= "White-space:pre" > </span>case 5: <span style= "White-space:pre" > </span>str = "Friday
";
<span style= "White-space:pre" > </span>break; <span style= "White-spacE:pre "> </span>case 6: <span style=" White-space:pre "> </span>str =" Saturday ";
<span style= "White-space:pre" > </span>break; <span style= "White-space:pre" > </span>case 7: <span style= "White-space:pre" > </span>str = "Sunday
";
<span style= "White-space:pre" > </span>break; } document.write ("Today is:" + str);

10. The Air triangle

for (var i = 0; i < 6; i++) {for
    (var j = 0; J < 5-i; j) {
       document.write ("");
    }
    for (var j = 0; J < 2 * i + 1; j + +) {
        if (j = = 0 | | j = = 2 * i)
           document.write ("*");
<span style= "White-space:pre" >	</span>else{
<span style= "White-space:pre" >	</ span>    document.write ("");
<span style= "White-space:pre" >	</span>}
document.write ("<br/>");
<span style= "White-space:pre" >	</span>if (i = 5)
<span style= "White-space:pre" >	</span>{
<span style= "White-space:pre" >	</span>for (var j = 0; J < 2 * i + 1; j + +)
&L T;span style= "White-space:pre" >	</span>document.write ("*");
        }

11.1-1/2+1/3-1/4+........-1/100 = 1+ ( -1/2) +1/3+ ( -1/4) ... + ( -1/100)

var sum = 0;
for (var i = 1;i <= i++) {
  if (i% 2 = 0) {
<span style= "White-space:pre" >	</span>sum = sum + -1 * (1/i);
   }
  else {
    sum = sum + 1/i;
  }
}
document.write (sum);