次の----から---までをメモ帳で作成し，"\rensyu\ex03.html"として保存する。
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<html>
<head>
<meta http-equiv="Content-Type" content="text/html;CHARSET=shift_jis">
<title>2次方程式の解法</title>
<script language="JavaScript">
<!--
function calc(a0, b0, c0)
{
var a, b, c, d, res;
a = a0; b = b0; c = c0;
if (a == 0) {
document.Result.result.value = "2次の項の係数がゼロです\n";
return;
}
res = a + "x^2 "
if (b > 0) {
res = res + "+ " + b + "x ";
}
else {
res = res + "- " + Math.abs(b) + "x ";
}
if (c > 0){
res = res + "+ " + c + "\n";
}
else {
res = res + "- " + Math.abs(c) + "\n";
}
d = b*b-4*a*c;
if (d > 0) {
if (b < 0) {
x1 = (-b-Math.sqrt(d))/2/a;
x2 = -b/a-x1;
}
else {
x1 = (-b+Math.sqrt(d))/2/a;
x2 = -b/a-x1;
}
document.Result.result.value = res + "２実解： x1 = " + x1 + ", x2 = " + x2 + "\n\n";
}
else if (d == 0) {
document.Result.result.value = res + "重解： x = " + (-b/2/a) + "\n\n";
}
else {
document.Result.result.value = res + "虚解： 実部 = " + (-b/2/a) + " 虚部 = " + (Math.sqrt(-d)/2/a) + "\n\n";
}
}
-->
</script>
</head>
<body bgcolor="#ffffff">
<h1>2次方程式の解</h1>
<form name=Result>
<p>
2次の係数<input name="data2" value=1 size=5>
1次の係数<input name="data1" value=1 size=5>
定数項<input name="data0" value=1 size=5>
</p>
<input type="button" name="calcurate" value="計 算" onClick="calc(this.form.data2.value, this.form.data1.value, this.form.data0.value)">
<input type="button" name="clear" value="入力欄クリア" onClick="this.form.data2.value=this.form.data1.value=this.form.data0.value=''">
<input type="button" name="clear" value="出力欄クリア" onClick="this.form.result.value=''"><p>
<p>
出力欄<br><textarea name="result" ROWS=5 COLS=70></textarea>
</p>
</form>
<hr>
<A HREF="javascript:history.go(-1)">直前のページへ戻る</A>
</body>
</html>
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