<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
</head>
<script language="javascript">
function countnum()
{
var num=0;
for(var i=0;i<document.all["mycheckbox"].length;i++)
{
if(document.all["mycheckbox"][i].checked==true)
{
num = num+1
}
}
alert(num)
}
</script>
<body>
<input type="submit" name="Submit" value="提交" onClick="countnum()">
<input type="checkbox" name="mycheckbox" value="checkbox" id="mycheckbox">
<input type="checkbox" name="mycheckbox" value="checkbox" id="mycheckbox">
<input type="checkbox" name="mycheckbox" value="checkbox" id="mycheckbox">
<input type="checkbox" name="mycheckbox" value="checkbox" id="mycheckbox">
<input name="mycheckbox" type="checkbox" value="checkbox" id="mycheckbox">
<input type="text" name="num">
</body>
</html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
</head>
<script language="javascript">
function countnum()
{
var num=0;
for(var i=0;i<document.all["mycheckbox"].length;i++)
{
if(document.all["mycheckbox"][i].checked==true)
{
num = num+1
}
}
alert(num)
}
</script>
<body>
<input type="submit" name="Submit" value="提交" onClick="countnum()">
<input type="checkbox" name="mycheckbox" value="checkbox" id="mycheckbox">
<input type="checkbox" name="mycheckbox" value="checkbox" id="mycheckbox">
<input type="checkbox" name="mycheckbox" value="checkbox" id="mycheckbox">
<input type="checkbox" name="mycheckbox" value="checkbox" id="mycheckbox">
<input name="mycheckbox" type="checkbox" value="checkbox" id="mycheckbox">
<input type="text" name="num">
</body>
</html>
试试这个结果:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
</head>
<script language="javascript">
function countnum()
{
var num=0;
for(var i=0;i<document.all["mycheckbox"].length;i++)
{
if(document.all["mycheckbox"][i].checked==true)
{
num = num+1
}
}
alert(num)
}
</script>
<body>
<input type="submit" name="Submit" value="提交" onClick="countnum()">
<input type="checkbox" name="mycheckbox" value="checkbox" id="mycheckbox">
<input type="text" name="num">
</body>
</html>