我有两个下拉菜单选择单位,如英寸,英尺e.t.c和用户所需的有效小数位后的有效数字,用于计算圆的面积和其他属性。 我没有任何编码经验,请不要介意代码。
<html>
<select name="rd" id="rd">
<script type="text/javascript">
for (var i = 1; i <= 10; i++) {
document.write("<option value=" + i + ">" + i + "</option>");
}
</script>
<script type="text/javascript">
function computeunit() {
//obtain user input
var dia = Number(document.getElementById("dia").value);
var diaunits = document.getElementById("diaunits").value;
var rn = document.getElementById("rd").value;
if (diaunits == "meter") dia /= 1.00;
if (diaunits == "inches") dia /= 39.3700787;
if (diaunits == "feet") dia /= 3.28084;
if (diaunits == "yard") dia /= 1.09361;
if (diaunits == "cm") dia /= 100;
if (diaunits == "mm") dia /= 1000;
var circumf = dia * Math.PI;
document.getElementById("txtcircumf").innerHTML = circumf;
var ar = (diaN / 2) * (diaN / 2) * Math.PI;
document.getElementsById("txtarea").innerHTML = ar;
var rs = new Number(circumf); // don't know how to include area
var nrs = rs.toFixed(rn);
document.getElementById("txtcircumf").value = nrs;
}
</script>
<pre>
<body>
<p>
Enter your diameter:
<input type="text" id="diaunits" />
<select type="multiple" id="diaunits">
<option value="metres" selected="selected">
metres
</option>
<option value="inches">
inches
</option>
<option value="feet">
feet
</option>
<option value="yard">
yard
</option>
<option value="centimeter">
centimeter
</option>
<option value="millimeter">
millimeter
</option>
</select>
</p>
Circumference:
<input type="text" id="txtcircumf" />
<input type="button" value="Calculate" onclick="computeunit();" />
</br>
Area:
<input type="text" id="txtarea" />
<input type="button" value="area" onclick="computeunit();" />
</br>
</body>
</pre>
<html>