JSlint:意外'换'

Question

我一直在测试单选按钮.一切似乎没问题,直到我通过JS lint运行它.我修复了除一个之外的所有错误

出乎意料的'为'

for (i = 0; i < radios.length; i += 1) {

这是我的Javascript:

/*global body,window,document,alert*/
(function () {
"use strict";

var UIlogic;

UIlogic = {
    myLoad: function () {
        var elems, elemText, btn1, winter, summer, fall, spring, header, btns;

        winter = "<div><input type='radio' name='cb' id='cbA' value='0'/><label for='cbA'>Winter</label></div>";
        summer = "<div><input type='radio' name='cb' id='cbB' value='1'/><label for='cbB'>Summer</label></div>";
        fall = "<div><input type='radio' name='cb' id='cbC' value='2'/><label for='cbC'>Fall</label></div>";
        spring = "<div><input type='radio' name='cb' id='cbD' value='3'/><label for='cbD'>Spring</label></div>";

        header = "Header";

        btns = "<br /><button class='btns' id='btn1'>Go!</button>";

        elemText = "Menu/nav";

        elems = "<center><div>" + header + "</div></center>";//title
        elems += "<div>" + elemText + "</div></center>";//menu
        elems += "<div id='container'><br />";//container opens
        elems += "<div id='div1'>" + winter + "</div>";
        elems += "<div id='div2'>" + summer + "</div>";
        elems += "<div id='div2'>" + fall + "</div>";
        elems += "<div id='div2'>" + spring + "</div>";
        elems += "<div id='div3'>" + btns + "</div>";
        elems += "</div>";//container closes
        elems += "<h6><div id='footer'>Ehawk 2015</div></h6>";

        body.innerHTML = elems;
        btn1 = document.getElementById("btn1");
        btn1.addEventListener('click', UIlogic.intoFunction, false);

    },
    intoFunction: function () {
        var radios, found, i = 0;
        radios = document.getElementsByName("cb");
        found = 1;
        for (i = 0; i < radios.length; i += 1) {//issue occurs here
            if (radios[i].checked) {
                alert(radios[i].value);
                found = 0;
                break;
            }
        }
        if (found === 1) {
            alert("Please Select Radio");
        }
    }
};
window.onload = function () {
    UIlogic.myLoad();
};
}());

我的循环错了吗？为什么JSlint会在这里看到问题,甚至认为代码有效？我真的可以对循环使用一些洞察力,因为我对它们的问题最多.我被告知不要使用它们,但我没有看到运行循环来检测单选按钮和检查无线电的问题.这是我应该关注的吗？

Answer 1

JSLint建议您使用其他循环,例如forEach.http://www.jslint.com/help.html#for

你可以在底部选择容忍"for statement"选项,如果这让你烦恼但代码看起来很好.

Answer 2

这是我能找到的最好的解释,

最近我决定不再需要使用for了.我完成了for循环.for发明了循环,它们来自Fortran.他们的目的是通过阵列的一种工作方式,但在ES5我们增加forEach()和map()和所有其它的,我当时想"是的,这是应该做的方式." 该for语法是如此怪异反正用在它的三个语句的东西.

Crockford继续谈论在ES6中完全使用循环结构,而只使用功能结构.

您可以选择忽略它 - 只需将选项传递给JSLint即可for.

但是,假设你决定取消for你拥有的循环.你可以用every().它会像(未经测试):

intoFunction: function () {
    var radios, found; 
    radios = document.getElementsByName("cb");
    found = Array.prototype.slice.call(radios).every(function(radio) {
        if (radio.checked) { 
            alert(radio.value); 
            return false; 
        }
        return true; 
    }); 

    if (found) {
        alert("Please Select Radio");
    }
}

在我看来,如果这更容易理解for循环,那说实话可言.老实说,这取决于您自己的个人/项目的编码标准.

更新了一个工作片段,演示every()如何实现此目的.

function into() {
  var radios, found;
  radios = document.getElementsByName("cb");
  found = Array.prototype.slice.call(radios).every(function(radio) {
    if (radio.checked) {
      alert(radio.value);
      return false;
    }
    return true;
  });

  if (found) {
    alert("Please Select Radio");
  }
}

jQuery("[name='cb']").on("click", into);
jQuery("button").on("click", function() {
  jQuery("[name='cb']").prop("checked", false);
  into();
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p>
  <label>
    <input type="radio" name="cb" value="M">Male</label>
</p>
<p>
  <label>
    <input type="radio" name="cb" value="F">Female</label>
</p>
<p>
  <label>
    <input type="radio" name="cb" value="I">I don't know</label>
</p>
<p>
  <label>
    <input type="radio" name="cb" value="B">Both</label>
</p>
<p>
  <button>Clear Radios</button>