The example in this article describes the method of using JavaScript to pop up a warning box when the check box exceeds the limit. Share it with everyone for your reference. The specific implementation method is as follows:
<html>
<title>javascript实现复选框超过限制即弹出警告框的方法</title>
<body>
<SCRIPT LANGUAGE="JavaScript">
<!--//
function countChoices(obj) {
max = 2;
box1 = obj.form.box1.checked;
box2 = obj.form.box2.checked;
box3 = obj.form.box3.checked;
count = (box1 ? 1 : 0) + (box2 ? 1 : 0) + (box3 ? 1 : 0);
if (count > max) {
alert("对不起，你只能选择" + max + "个项目!");
obj.checked = false;
}
}
//-->
</script>
<form name="form">
请最多选择2个项目：
<p>
<input type=checkbox name=box1 onClick="countChoices(this)">
选择项目1
<p>
<input type=checkbox name=box2 onClick="countChoices(this)">
选择项目2
<p>
<input type=checkbox name=box3 onClick="countChoices(this)">
选择项目3
<p>
<div>
</div>
</FORM>
</body>
</html>I hope this article will be helpful to everyone’s JavaScript programming design.
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