找了好久为啥就是没效果啊

<!DOCTYPE html>

<html>

<head>

function count(){

//获取第一个输入框的值

var num1 = parseInt(document.getElementById("txt1").value);

//获取第二个输入框的值

var num2 = parseInt(document.getElementById("txt2").value)

//获取选择框的值

var select = document.getElementById("select").value;

//获取通过下拉框来选择的值来改变加减乘除的运算法则

var sum=0;

switch(select){

case '+':

sum = (num1+num2);

break;

case '-':

sum = (num1-num2);

break;

case '*':

sum = (num1*num2);

break;

case '/':

sum = (num1/num2);

break;

default:

sum = 0;

break;

}

document.getElementById("fruit").value = sum;

}

</script>

</head>

<body>

</select>

</body>

</html>

小菜鸡的

浏览 548回答 1