My simple Javascript exercises colection starts from page: Some simple Javascript exercises. In this article I propose more.

Exercise 4
Solve a second order equation

<!DOCTYPE html>
<html><head>
<script>
function equation2degree() {
  var a = document.getElementById("number1").value;
  a=parseFloat(a);
  var b = document.getElementById("number2").value;
  b=parseFloat(b);
  var c = document.getElementById("number3").value;
  c=parseFloat(c);
  var delta = b*b-(4*a*c);
  if (delta < 0)
  {
     document.getElementById("solution").innerHTML = "Impossible";
  }
  else
  {
     var x1=(-b+Math.sqrt(delta))/(2*a);
     var x2=(-b-Math.sqrt(delta))/(2*a);         
     document.getElementById("solution").innerHTML = "x<sub>1</sub>=" + x1 + "&nbsp;&nbsp;x<sub>2</sub>=" + x2;
  }
}
</script>
</head><body>
  <h3>Solve a second order equation in the form ax<sup>2</sup>+bx+c=0</h3>
  <p>Insert the coefficients (integer or real numbers, with negative sign if present)<BR><BR>
  a: <input type="text" id="number1"><BR><BR>
  b: <input type="text" id="number2"><BR><BR>
  c: <input type="text" id="number3"><BR><BR>
  <button onclick="equation2degree()">Solve!</button></p>
  <p>Solution:&nbsp;&nbsp;<span id="solution"></span></p>
</body></html>


Exercise 5

Determine if a year is a leap year.
All years whose number represents them is a multiple of 4, are leap years, except for secular years (ie multiples of 100) if their number is not a multiple of 400.

<!DOCTYPE html>
<html><head>
<script>
function leapYear() {
  var year = parseInt(document.getElementById("year").value);
  var leap = false;
  if (year%100==0)   // is it a secular year?
  {
    if (year%400==0)
    {
      leap = true;
    }
  }
  else   // all other years!
  {
    if (year%4==0)
    {
      leap = true;
    }
  }
 
document.getElementById("print").innerHTML = leap;
}
</script>
</head><body>
  <h3>Tell me a year and I determine if it is a leap year!</h3>
  Gimme the year: <input type="number" id="year">
  <button onclick="leapYear()">Submit</button>
  <BR><p>Answer: <span  id="print"></span></p><BR>
</body></html>

 


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