HTML表单javascript，用于关联问题、答案和反馈
HTML表单javascript，用于关联问题、答案和反馈
提问于 2019-02-02 21:44:54
我在HTML表单中有一个语言测验，当用户检查他们的输入时，反馈会以勾号或十字图标的形式插入到单元格中。我的问题是，无论第一个还是第二个问题得到回答和检查，反馈总是插入到第一个td中。问题和适当的答案与elementNo相关联:我不知道如何将“标记”单元格与其答案和问题相关联
<SCRIPT>
//Define the answers.
Answer = new Array( "Die Maus ist weiss.", "",
"Auf Wiedersehen!");
//inserts icon, however only in the first element named "mark".
// Somehow needs to select correct place according to element number
function itemfeedback (elementNo)
{
if (document.E1a.elements[elementNo].value == "")
{
alert("You must type an answer!");
}
else if (document.E1a.elements[elementNo].value == Answer[elementNo])
{
document.getElementById("mark").innerHTML = "<img src='correct.jpg'>";
}
else
{
document.getElementById("mark").innerHTML = "<img src='incorrect.jpg'>";
}
}
</SCRIPT>
</HEAD>
<BODY>
<FORM NAME="E1a" accept-charset="ISO-8859-1" onReset="return confirm('Clear entries? Are you sure?')">
<HR>
<H3>
translate, remembering punctuation and capitalisation...
</H3>
<table>
<tr>
<td>1. The mouse is white.</td>
<td><INPUT TYPE="TEXT" NAME="Q1" SIZE=50 MAXLENGTH=50></td>
<td><INPUT TYPE="button" id ="check_button" VALUE="check..." NAME="B1" onClick="itemfeedback(0)"></td>
<td id="mark"></td>
</tr>
<tr>
<td>2. Good-bye!</td>
<td><INPUT TYPE="TEXT" NAME="Q2" SIZE=50 MAXLENGTH=50></td>
<td><INPUT TYPE="button"id ="check_button" VALUE="check..." NAME="B2" onClick="itemfeedback(2)"></td>
<td id="mark"></td>
</tr>
</table>
<hr>
<INPUT TYPE="RESET" id ="reset_fields" VALUE="Clear Entries">
</CENTER>
</FORM>
</BODY>
</HTML>我希望我的问题是清楚的，并且有人会帮助我。
回答 1
Stack Overflow用户
回答已采纳
发布于 2019-02-03 13:02:40
快速回答
根据HTML5 specs，ID在一个超文本标记语言文档中应该是唯一的。因此，ID在第一次出现后的所有实例都会被JavaScripts "getElementById“函数忽略。选择多个DOM元素的更合适的方法是使用"class“属性，如下所示：
<td class="mark"></td>
...
<td class="mark"></td>并使用JavaScript引用它，使用"getElementsByClassName“
document.getElementsByClassName('mark')更有帮助的答案
我会再提几个建议，让你的代码更具动态性和功能性。我在下面的代码中插入了注释，以解释我所做的更改/建议。
<html>
<head>
<script>
// We will use an object instead of an array, so that we can reference the answers by a string, rather then an integer.
// Also, any time a NEW variable is defined, it should be prefaced with "let" or "const" for >= ES2015, or "var" for < ES2015 (see https://codeburst.io/javascript-wtf-is-es6-es8-es-2017-ecmascript-dca859e4821c for details on the different script versions)
const answer = {
Q1: "Die Maus ist weiss.",
Q2: "Auf Wiedersehen!"
};
// itemfeedback function is now passing the input id, rather than the index
function itemfeedback (id) {
// This will get the input, associated with the button
let input = document.getElementById(id),
// This will be the ID of the mark element that is associated with the submitted input
markId = "mark" + id,
// This is the mark element assocaited with the submitted input
mark = document.getElementById(markId);
if (input.value == "") {
alert("You must type an answer!");
}
// Since we have assigned the answers to an object, and gave each of the answers indexes to match the input ids, we can find the answer by that
else if (input.value == answer[id]){
mark.innerHTML = "<img src='correct.jpg'>";
} else {
mark.innerHTML = "<img src='incorrect.jpg'>";
}
}
</script>
</head>
<body>
<form NAME="E1a" accept-charset="ISO-8859-1" onReset="return confirm('Clear entries? Are you sure?')">
<HR>
<H3>
translate, remembering punctuation and capitalisation...
</H3>
<table>
<tr>
<td>1. The mouse is white.</td>
<!-- Gave input ID of "Q1" -->
<td><input TYPE="TEXT" NAME="Q1" SIZE=50 MAXLENGTH=50 id="Q1"></td>
<!-- Changed id to class, since it is non-unique -->
<td><input TYPE="button" class="check_button" value="check..." NAME="B1" onClick="itemfeedback('Q1')"></td>
<!-- We will give this an ID that can be associated with it's related inputs name attribute -->
<td id="markQ1"></td>
</tr>
<tr>
<td>2. Good-bye!</td>
<!-- Gave input ID of "Q2" -->
<td><input TYPE="TEXT" NAME="Q2" SIZE=50 MAXLENGTH=50 id="Q2"></td>
<!-- Passed ID to onChange handler, instead of index. Also hanged id to class, since it is non-unique -->
<td><input TYPE="button" class="check_button" value="check..." NAME="B2" onClick="itemfeedback('Q2')"></td>
<!-- We will give this an ID that can be associated with it's related inputs name attribute -->
<td id="markQ2"></td>
</tr>
</table>
<hr>
<input TYPE="RESET" id="reset_fields" value="Clear Entries">
</center>
</form>
</body>
</html>编辑以重置表单
放置此函数可从form onReset中删除图像：
<!-- We are now calling a function to be executed, and the returned value of the function will determine if the form itself is cleared. A negative blue will not, a positive value will -->
<form NAME="E1a" accept-charset="ISO-8859-1" onReset="return clearForm(this)">function clearForm (form) {
// Get option that is pressed
var clear = confirm('Clear entries? Are you sure?');
// If positive option is clicked, the form will be reset
if (clear) {
// This will select all images within the document
var markImgs = document.getElementsByTagName('img');
// Iterates through each image, and removes it from the dom
while (markImgs[0]) markImgs[0].parentNode.removeChild(markImgs[0])
}
return clear;
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/54493642
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