[英]Calculator on JavaScript(simple)
在文本字段中,您需要指定值并通过按钮对其进行计数。 我不明白为什么不这样认为? 您原则上需要通过一个开关来实现它,但我不明白为什么不计算操作数:+,-,*,/
<p>
<label for="text1">FirstNum</label>
<input type="text" id="text1"><br>
<label for="operation">Operation</label>
<input type="text" id="operation"><br>
<label for="text2">SecondNum</label>
<input type="text" id="text2"><br>
<label for="text3">Result</label>
<input type="text" id="text3"><br><br>
<input type="button" value="ClickResult" onclick="Calc()">
</p>
<script>
function Calc(operation) {
//var op;
switch(operation) {
case '+':
text3.value = text1.value + text2.value;
break;
case '-':
text3.value = text1.value - text2.value;
break;
case '/':
text3.value = text1.value / text2.value;
break;
case '*':
text3.value = text1.value * text2.value;
break;
}
}
</script>
您需要像这样获取文本框的值:
var text1 = document.getElementById('text1').value;
但是您获得的值是字符串格式,因此您需要将其转换为int或float,因此必须将其转换为int或float,如下所示:
text1 = parseFloat(text1);
然后在结果框中给出值,如下所示:
document.getElementById('text3').value = result of the calculation
或另一种方式是:
var result = document.getElementById('text3');
result.value = result of computation
<p> <label for="text1">FirstNum</label> <input type="text" id="text1"><br> <label for="operation">Operation</label> <input type="text" id="operation"><br> <label for="text2">SecondNum</label> <input type="text" id="text2"><br> <label for="text3">Result</label> <input type="text" id="text3"><br><br> <input type="button" value="ClickResult" onclick="Calc()"> </p> <script> function Calc() { var text1 = document.getElementById('text1').value; var text2 = document.getElementById('text2').value; var operation = document.getElementById('operation').value; var text3 = document.getElementById('text3'); text1 = parseFloat(text1); text2 = parseFloat(text2); //var op; switch(operation) { case '+': text3.value = text1 + text2; break; case '-': text3.value = text1 - text2; break; case '/': text3.value = text1 / text2; break; case '*': text3.value = text1 * text2; break; } } </script>
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