javascript 在javascript中检索组合框值
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时间：2020-10-27 05:53:49 来源:igfitidea点击:
Retrieve combobox value in javascript
提问by giacomotb
This is my little program, what could i do for take the combobox value??
这是我的小程序，我可以做什么来获取组合框值？
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<link rel="stylesheet" type="text/css" href="NewFile.css">
<title>Insert title here</title>
<script type="text/javascript">
function calcola(){
var op = String(document.getElementById("combo").value);
alert(op);
}
</script>
</head>
<body>
<div class="in">
Inserire il primo numero:
<input type="text" id="primo">
<br>
Inserire il secondo numero:
<input type="text" id="secondo">
</div>
<div class="in">
<select id="combo">
<option selected="selected">*</option>
<option>/</option>
<option>+</option>
<option>-</option>
</select>
</div>
<div>
<input type="button" name="bottone" value="Premi" onclick="calcola();">
</div>
</body>
</html>
This program should be a calculator, but I omitted most of code because it's necessary to know the operator befor doing calculations.
这个程序应该是一个计算器，但我省略了大部分代码，因为在进行计算之前需要了解运算符。
回答by Harsha Venkatram
Try this
试试这个
function calcola()
{
var element = document.getElementById("combo");
var op = element.options[element.selectedIndex].value;
alert(op);
}
回答by Niccolò Campolungo
Inside your function:
在你的函数中：
function calcola(){
var elt = document.getElementById("combo"),
op = elt.options[elt.selectedIndex].text;
alert(op);
}
Buon lavoro collega italiano ;)
Buon lavoro collega italiano ;)
