使用按钮循环遍历数组

时间:2013-10-26 02:53:50

标签: javascript html css events dom-manipulation

好的,本质上我想创建一个包含下一个和上一个按钮的简短测验。我想循环遍历两个数组,问题和选择,并在最后得分。我已经阅读了有关DOM和事件的章节,但它并没有明显地点击。

我真的需要一些代码来展示如何操作DOM的具体示例。到目前为止我只有数组,并且声明x实际上是通过id获取我的元素的函数。哈哈。

抱歉,我没有更多代码可以提供。我试图将id附加到一个段落,然后通过它的id和document.write数组得到它,但是它取代了按钮。如果你运行下面的代码,你会看到我在说什么。

<!DOCTYPE html>
<html>
<head>
    <title>Bom</title>
</head>
<body>
    <input type="button" value="Iterate" id="myButton" onclick="iter_onclick()">
    <p id="qArray">Some Text</p>

    <script>
        var qArray = ["Who is my dog?", "who is the prez?", "Who is my girlfriend?", "Who am I?"];

        var cArray = [["Bill","Billy", "Arnold", "Tyler"],["Oz"," Buffon","Tupac","Amy"],["Tony Blair","Brack Osama","Barack Obama","Little Arlo"],["Emma Stone","Tony the Tiger","","The Smurf Girl"]];

        function iter_onclick () {
            var x = document.getElementById("qArray");
            document.write("Hello World");
        }        
     </script>
</body>
</html>`

就像我说的,这是我第一次尝试真正操纵DOM,我知道自己想做什么。我只是不知道该怎么做。我理解所有的语法和事件和对象等。但是,我不确定如何应用它。此外,没有Jquery。我想知道如何使用Javascript创建应用程序,然后以我的方式进入Jquery。谢谢大家。

2 个答案:

答案 0 :(得分:1)

这是一个非常基本的例子。这会修改现有的DOM项。您不能在已加载的文档上使用document.write(),也不会清除所有内容并重新开始,这不是将内容放入DOM的最有效方式。

此示例在页面上有许多字段,它会加载一个问题,然后在您按下下一个按钮时检查答案。

HTML:

<div id="question"></div>
<input id="answer" type="text"><br><br>
<button id="next">Next</button>  <br><br><br>
Number Correct So Far: <span id="numCorrect">0</span>

Javascript(在脚本标记中):

var qArray = ["Who is my dog?", "who is the prez?", "Who is my girlfriend?", "Who am I?"];

var cArray = [["Bill","Billy", "Arnold", "Tyler"],["Oz"," Buffon","Tupac","Amy"],["Tony Blair","Brack Osama","Barack Obama","Little Arlo"],["Emma Stone","Tony the Tiger","Amy Dahlquist","The Smurf Girl"]];

var questionNum = -1;
var numCorrect = 0;

function loadQuestion() {
    ++questionNum;
    if (questionNum >= qArray.length) {
        alert("all questions are done");
    } else {
        document.getElementById("question").innerHTML = qArray[questionNum];
        document.getElementById("answer").value = "";
    }
}

loadQuestion();

function checkAnswer() {
    var answer = document.getElementById("answer").value.toLowerCase();
    var allowedAnswers = cArray[questionNum];
    for (var i = 0; i < allowedAnswers.length; i++) {
        if (allowedAnswers[i].toLowerCase() == answer) {
            return true;
        }
    }
    return false;
}

document.getElementById("next").addEventListener("click", function(e) {
    if (checkAnswer()) {
        ++numCorrect;
        document.getElementById("numCorrect").innerHTML = numCorrect;
        loadQuestion();
    } else {
        alert("Answer is not correct");
    }
});

工作演示:http://jsfiddle.net/jfriend00/gX2Rm/

答案 1 :(得分:1)

这将循环你的问题,希望这可以帮助你继续。

var qArray = ["Who is my dog?", 
       "who is the prez?", 
       "Who is my girlfriend?", 
       "Who am I?"];

var cArray = [
    ["Bill", "Billy", "Arnold", "Tyler"],
    ["Oz", " Buffon", "Tupac", "Amy"],
    ["Tony Blair", "Brack Osama", "Barack Obama", "Little Arlo"],
    ["Emma Stone", "Tony the Tiger", "Amy Dahlquist", "The Smurf Girl"]
];

var index = 0;

function iter_onclick() {
    //if this is the last question hide and displays quiz ends            
    if (index >= qArray.length) {
        document.getElementById('qArray').innerHTML = '<div>Quiz End, Thank you</div>'
        document.getElementById('myButton').style.visibility = 'hidden ';
        return false;
    }

    var html = ' <div> ' + qArray[index] + ' </div> <div>';
    for (var i = 0; i < cArray[index].length; i++) {
        html += '<label><input type="radio" name="ans" value="' 
             + cArray[index][i] + '"/ > ' + cArray[index][i] + ' </label>';
    }
    html += '</div > ';
    document.getElementById('qArray').innerHTML = html;

    index++;
}