function add()
{
var num = document.getElementById("count").value;
num += 1;
alert(num);
document.getElementById("count").innerHTML = num;
}
点击触发add()事件,使num加1,然后在文本框里改变数值.我的代码怎样修改? 求高手解决.
{
var num = document.getElementById("count").value;
num += 1;
alert(num);
document.getElementById("count").innerHTML = num;
}
点击触发add()事件,使num加1,然后在文本框里改变数值.我的代码怎样修改? 求高手解决.
var num = parseInt(document.getElementById("count").value);
if (isNaN(num)) num = 0;
num += 1;
alert(num);
document.getElementById("count").value = num;
}
{
var num = document.getElementById("count").value;
num = num + 1;
document.getElementById("count").value = num;
}
function minus()
{
var num = document.getElementById("count").value;
num -= 1;
document.getElementById("count").value = num;
}
现在不能实现加等,减等可以单个实现.
怎么不行啊》?你怎么测试的???
把下面的代码存储成htm,浏览测试<body>
<input id="count" value="100">
<input type=button value="+=" onclick="add()">
<input type=button value="-=" onclick="minus()"><script>
function add() {
var num = parseInt(document.getElementById("count").value);
if (isNaN(num)) num = 0;
num += 1;
alert(num);
document.getElementById("count").value = num;
}
function minus()
{
var num = parseInt(document.getElementById("count").value);
if (isNaN(num)) num = 0;
num -= 1;
document.getElementById("count").value = num;
}</script>