6-11编程练习为什么我的计算器减法除法乘法都正常，唯独加法2+3会等于23呢？

源自：6-11 编程练习

<!DOCTYPE html>

<html>

<head>

function count(){

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

var txt2=document.getElementById("txt2").value;

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

var result;

switch(select){

case "+":

result=txt1+txt2;

break;

case "-":

result=txt1-txt2;

break;

case "*":

result=txt1*txt2;

break;

case "/":

if(txt2==0){

alert("0不能做被除数！")

}

result=txt1/txt2;

break;

}

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

}

</script>

</head>

<body>

</select>

</body>

</html>

提问者：__呵呵哒_ 2016-09-27 10:51