使用Javascript验证单选按钮 [英] Validation of radio buttons with Javascript

问题描述

我已经在这里梳理了大量的页面，但仍然无法让我的显式验证器工作。基本上，当单击提交按钮时，我希望脚本验证是否检查了无线电，如果检查了无线电。如果没有选中，我希望它发布一条警告信息。

I've combed a ton of the pages on here, and still am incapable to get my explicit validator to work. Basically, when the submit button is clicked, I want the script to verify a radio is checked, if one is checked to do nothing. If one isn't checked I want it to post an alert message.

大致上我的html看起来像：

roughly my html looks like:

<form id="myForm" onsubmit = "check()">
<input type = "radio" name = "c" id = "1" value = "1" />
<input type = "radio" name = "c" id = "2" value = "2" />
<input type = "radio" name = "c" id = "3" value = "3" />

<input type = "submit" value = "Submit" />

---

我的JS页面如下：

---

my JS page looks like:

function check() {
    var r = document.getElementsByName("c")
    var c = 0

    for(var i=0; i < r.length; i++){
       if(c[i].checked) {
          c = i; }
    }

    alert("please select radio");
}

推荐答案

试试这个

function check() {
var r = document.getElementsByName("c")
var c = -1

for(var i=0; i < r.length; i++){
   if(r[i].checked) {
      c = i; 
   }
}
if (c == -1) alert("please select radio");
}

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