CodeForPower.org/calculator.html at master · Jack-Zhou27/CodeForPower.org · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
  <title>Quadratic Equation Solver</title>

  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"></script>
    <script>
        var a, b, c;
        var outputText;

        function validate() {

            // get the input
            a = document.forms["input_form"]["aterm"].value;
            b = document.forms["input_form"]["bterm"].value;
            c = document.forms["input_form"]["cterm"].value;

            // validate a, b and c
            if (a == 0) {
                outputText = "<em>a</em> cannot equal zero!";
            } else if (isNaN(a)) {
                outputText = "<em>a</em> must be a number!";
            } else if (isNaN(b)) {
                outputText = "<em>b</em> must be a number!";
            } else if (isNaN(c)) {
                outputText = "<em>c</em> must be a number!";
            } else {
                // calculate the result using x = (-b +- sqrt(b^2 - 4ac)) / 2a
                var x1 = (-b - Math.sqrt(Math.pow(b, 2) - 4 * a * c)) / (2 * a);
                var x2 = (-b + Math.sqrt(Math.pow(b, 2) - 4 * a * c)) / (2 * a);
                outputText = "For the equation <strong>" + (a == 1 ? "" : a) + "x\u00B2 + " + (b == 1 ? "" : b) + "x + " + c + " = 0</strong>, x can equal <strong>" + x1 + "</strong> or <strong>" + x2 + "</strong>";
            }

            // output the result (or errors)
            document.getElementById("output_text").innerHTML = outputText;
        }
    </script>
	<nav class="navbar navbar-inverse">
  <div class="container-fluid">
    <div class="navbar-header">
      <a class="navbar-brand" href="BearyHome.html">Beary</a>
    </div>
    <ul class="nav navbar-nav">
      <li class="active"><a href="NavigationBar.html">Home</a></li>

      <li><a href="page2OFtheWebsite.html">Competitive Programming123</a></li>
		<li><a href="calculator.html">calculator</a></li>
      <li><a href="JavaBasics.html">Java Basics</a></li>
    </ul>
    <ul class="nav navbar-nav navbar-right">
      <li><a href="#"><span class="glyphicon glyphicon-user"></span> Sign Up</a></li>
      <li><a href="#"><span class="glyphicon glyphicon-log-in"></span> Login</a></li>
    </ul>
  </div>
</nav>
</head>
<body>


	<center>
    <p>Please enter the coefficients <strong>a</strong>, <strong>b</strong> and <strong>c</strong> of a quadratic equation of the form <strong>ax&#x00B2; + bx + c = 0</strong></p>

    <form name="input_form" action="javascript:validate();">
        a: <input type="text" name="aterm" size="5" required>
        b: <input type="text" name="bterm" size="5" required>
        c: <input type="text" name="cterm" size="5" required>
        <br><br>
        <input type="submit" value="Calculate">
    </form>

    <p id="output_text"/>
	</center>
</body>
</html>