Javascript 事件仅在应用于多个元素时触发一次
我正在用纯JS动态创建一个表单。每当最后一个输入字段收到输入时，应创建另一个空字段。另一方面，当最后一个字段之前的字段也变为空时，应删除最后一个字段 HTML（用户输入前）：Javascript 事件仅在应用于多个元素时触发一次,javascript,html,events,dom-events,addeventlistener,Javascript,Html,Events,Dom Events,Addeventlistener,我正在用纯JS动态创建一个表单。每当最后一个输入字段收到输入时，应创建另一个空字段。另一方面，当最后一个字段之前的字段也变为空时，应删除最后一个字段 HTML（用户输入前）： Javascript（随后实现；摘录）： 函数addBox（）{ var-box=document.getElementsByClassName（“eventBox”）； var id=+getMaxID（框，“事件”）++1；//正在创建的输入的id var list=document.getElementById
函数addBox（）{
var-box=document.getElementsByClassName（“eventBox”）；
var id=+getMaxID（框，“事件”）++1；//正在创建的输入的id
var list=document.getElementById（“事件列表”）；
list.innerHTML=list.innerHTML+'
'；
document.getElementById（“事件”+id）.addEventListener（“输入”，resizeEventList）；
}
函数delBox（）{
loadText（）；//保存当前输入
var list=document.getElementById（“事件列表”）；
document.getElementById（“eventList”）.innerHTML=''；
var-id=1；
对于（var i=1；i0）{
/*使用以前的输入重新创建框（如果不是空的）*/
document.getElementById（“事件列表”）.innerHTML=document.getElementById（“事件列表”）.innerHTML+'
'；
document.getElementById（“事件”+id）.addEventListener（“输入”，resizeEventList）；
id++；
}
}
/*添加新的最后一个空输入*/
document.getElementById（“事件列表”）.innerHTML=document.getElementById（“事件列表”）.innerHTML+'
'；
document.getElementById（“事件”+id）.addEventListener（“输入”，resizeEventList）；
}
函数resizeEventList（e）{
如果（类型e！=“未定义”）{
var-box=document.getElementsByClassName（“eventBox”）；
if（e.target.id==“event”+getMaxID（框，“event”）&&e.type==“input”）{
/*输入到最后一个可用框->添加一个空框*/
loadText（）；//保存当前输入
senderID=e.target.id；//记住触发元素的id，以便以后重置焦点
addBox（）；//添加另一个框
WriteText（）；//将以前的输入写回框中
document.getElementById（senderID）.focus（）；//重置焦点
}else if（e.target.value.length==0&&getID（e.target，“事件”）删除最后一个空框*/
senderID=e.target.id；//记住触发元素的id，以便以后重置焦点
delBox（）；//删除所有框并创建X个新框
document.getElementById（senderID）.focus（）；//重置焦点
}
}
}
var eventtext=新数组（）；
森德里德变种；
document.getElementById（“event1”）.addEventListener（“输入”，resizeEventList）；
<form id="planForm" class="top-margin" method="post" action="new.php?action=add">
<div>
<input class="text head bold" type="date" name="date" placeholder="Datum" value="<?php echo date("Y-m-d", time());?>" required /> <br>
<div id="eventList" class="gap">
<input id="event1" class="text bold eventBox" type="text" name="event1" placeholder="Ereignis 1" /> <br>
</div>
</div >
<input type="button" value="Speichern" onclick="save();" / >
</form>
<script>
function getID(elm, type) {
if (typeof elm != 'undefined') {
return elm.id.replace(type, "");
} else {
return "";
}
}
function getMaxID(list, type) {
currID = 0;
max = 0;
if (list != null && list.length > 0 && type != null) {
for (var i=0; i < list.length; i++) {
currID = getID(list[i], type);
if ( currID > max ) {
max = currID;
}
}
}
return max;
}
function addBox() {
var boxes = document.getElementsByClassName("eventBox");
var id = +getMaxID(boxes, "event") + +1; // ID of input being created
var list = document.getElementById("eventList");
list.innerHTML = list.innerHTML + '<input id="event'+ id +'" class="text bold eventBox" type="text" name="event'+ id +'" placeholder="Ereignis '+ id +'" /> <br>';
document.getElementById("event" + id).addEventListener("input", resizeEventList);
console.log(document.getElementById("event" + id));
}
function delBox() {
loadTexts(); // save current inputs
var list = document.getElementById("eventList");
document.getElementById("eventList").innerHTML = '';
var id = 1;
for (var i = 1; i < eventTexts.length; i++) {
if (eventTexts[i].length > 0) {
/* recreate box with its former input (if not empty) */
document.getElementById("eventList").innerHTML = document.getElementById("eventList").innerHTML + '<input id="event'+ id +'" class="text bold eventBox" type="text" name="event'+ id +'" placeholder="Ereignis '+ id +'" value="' + eventTexts[i] + '"/> <br>';
document.getElementById("event" + id).addEventListener("input", resizeEventList);
id++;
}
}
/* add new last empty input */
document.getElementById("eventList").innerHTML = document.getElementById("eventList").innerHTML + '<input id="event'+ id +'" class="text bold eventBox" type="text" name="event'+ id +'" placeholder="Ereignis '+ id +'" value=""/> <br>';
document.getElementById("event" + id).addEventListener("input", resizeEventList);
}
function resizeEventList(e) {
if (typeof e != 'undefined') {
var boxes = document.getElementsByClassName("eventBox");
if (e.target.id == "event"+getMaxID(boxes, "event") && e.type == 'input') {
/* input into last available box -> add an empty box */
loadTexts(); // save current inputs
senderID = e.target.id; // remember ID of triggering element for resetting focus afterwards
addBox(); // add another box
writeTexts(); // write former inputs back into boxes
document.getElementById(senderID).focus(); // reset focus
} else if (e.target.value.length == 0 && getID(e.target, "event") < getMaxID(boxes, "event")) {
/* box before last box empty -> delete last empty box */
senderID = e.target.id; // remember ID of triggering element for resetting focus afterwards
delBox(); // delete all boxes and create X new boxes
document.getElementById(senderID).focus(); // reset focus
}
}
}
function loadTexts() {
var boxes = document.getElementsByClassName("eventBox");
for (var i=0; i < boxes.length; i++) {
eventTexts[getID(document.getElementById(boxes[i].id), "event")] = boxes[i].value;
}
}
function writeTexts() {
var boxes = document.getElementsByClassName("eventBox");
for (var i=0; i < boxes.length-1; i++) {
document.getElementById(boxes[i].id).value = eventTexts[getID(boxes[i], "event")];
}
}
var eventTexts = new Array();
var senderID;
document.getElementById("event1").addEventListener("input", resizeEventList);
</script>
对于每个想了解解决方案的人：
使用“insertAdjacentHTML”而不是“innerHTML”动态创建元素。感谢RajeshP提供了一个指向此有用答案的链接：在添加侦听器之前，您是否已注销并实际获取了页面上的元素？是的，我获得了正确的ID，但仅在第一次输入之后。进一步的输入根本不会触发事件。您是否看到这是否返回元素？getElementById（“事件”+id）是的，它会被返回。奇怪的是：动态添加的监听器和event1的监听器都可以正常工作，但只能工作一次。之后，它们似乎都不再触发事件了。问题可能是使用innerHTML追加新的输入。有关类似问题，请参见此答案。
function addBox() {
var boxes = document.getElementsByClassName("eventBox");
var id = +getMaxID(boxes, "event") + +1; // ID of input being created
var list = document.getElementById("eventList");
list.innerHTML = list.innerHTML + '<input id="event'+ id +'" class="text bold eventBox" type="text" name="event'+ id +'" placeholder="Ereignis '+ id +'" /> <br>';
document.getElementById("event" + id).addEventListener("input", resizeEventList);
}
function delBox() {
loadTexts(); // save current inputs
var list = document.getElementById("eventList");
document.getElementById("eventList").innerHTML = '';
var id = 1;
for (var i = 1; i < eventTexts.length; i++) {
if (eventTexts[i].length > 0) {
/* recreate box with its former input (if not empty) */
document.getElementById("eventList").innerHTML = document.getElementById("eventList").innerHTML + '<input id="event'+ id +'" class="text bold eventBox" type="text" name="event'+ id +'" placeholder="Ereignis '+ id +'" value="' + eventTexts[i] + '"/> <br>';
document.getElementById("event" + id).addEventListener("input", resizeEventList);
id++;
}
}
/* add new last empty input */
document.getElementById("eventList").innerHTML = document.getElementById("eventList").innerHTML + '<input id="event'+ id +'" class="text bold eventBox" type="text" name="event'+ id +'" placeholder="Ereignis '+ id +'" value=""/> <br>';
document.getElementById("event" + id).addEventListener("input", resizeEventList);
}
function resizeEventList(e) {
if (typeof e != 'undefined') {
var boxes = document.getElementsByClassName("eventBox");
if (e.target.id == "event"+getMaxID(boxes, "event") && e.type == 'input') {
/* input into last available box -> add an empty box */
loadTexts(); // save current inputs
senderID = e.target.id; // remember ID of triggering element for resetting focus afterwards
addBox(); // add another box
writeTexts(); // write former inputs back into boxes
document.getElementById(senderID).focus(); // reset focus
} else if (e.target.value.length == 0 && getID(e.target, "event") < getMaxID(boxes, "event")) {
/* box before last box empty -> delete last empty box */
senderID = e.target.id; // remember ID of triggering element for resetting focus afterwards
delBox(); // delete all boxes and create X new boxes
document.getElementById(senderID).focus(); // reset focus
}
}
}
var eventTexts = new Array();
var senderID;
document.getElementById("event1").addEventListener("input", resizeEventList);
<form id="planForm" class="top-margin" method="post" action="new.php?action=add">
<div>
<input class="text head bold" type="date" name="date" placeholder="Datum" value="<?php echo date("Y-m-d", time());?>" required /> <br>
<div id="eventList" class="gap">
<input id="event1" class="text bold eventBox" type="text" name="event1" placeholder="Ereignis 1" /> <br>
</div>
</div >
<input type="button" value="Speichern" onclick="save();" / >
</form>
<script>
function getID(elm, type) {
if (typeof elm != 'undefined') {
return elm.id.replace(type, "");
} else {
return "";
}
}
function getMaxID(list, type) {
currID = 0;
max = 0;
if (list != null && list.length > 0 && type != null) {
for (var i=0; i < list.length; i++) {
currID = getID(list[i], type);
if ( currID > max ) {
max = currID;
}
}
}
return max;
}
function addBox() {
var boxes = document.getElementsByClassName("eventBox");
var id = +getMaxID(boxes, "event") + +1; // ID of input being created
var list = document.getElementById("eventList");
list.innerHTML = list.innerHTML + '<input id="event'+ id +'" class="text bold eventBox" type="text" name="event'+ id +'" placeholder="Ereignis '+ id +'" /> <br>';
document.getElementById("event" + id).addEventListener("input", resizeEventList);
console.log(document.getElementById("event" + id));
}
function delBox() {
loadTexts(); // save current inputs
var list = document.getElementById("eventList");
document.getElementById("eventList").innerHTML = '';
var id = 1;
for (var i = 1; i < eventTexts.length; i++) {
if (eventTexts[i].length > 0) {
/* recreate box with its former input (if not empty) */
document.getElementById("eventList").innerHTML = document.getElementById("eventList").innerHTML + '<input id="event'+ id +'" class="text bold eventBox" type="text" name="event'+ id +'" placeholder="Ereignis '+ id +'" value="' + eventTexts[i] + '"/> <br>';
document.getElementById("event" + id).addEventListener("input", resizeEventList);
id++;
}
}
/* add new last empty input */
document.getElementById("eventList").innerHTML = document.getElementById("eventList").innerHTML + '<input id="event'+ id +'" class="text bold eventBox" type="text" name="event'+ id +'" placeholder="Ereignis '+ id +'" value=""/> <br>';
document.getElementById("event" + id).addEventListener("input", resizeEventList);
}
function resizeEventList(e) {
if (typeof e != 'undefined') {
var boxes = document.getElementsByClassName("eventBox");
if (e.target.id == "event"+getMaxID(boxes, "event") && e.type == 'input') {
/* input into last available box -> add an empty box */
loadTexts(); // save current inputs
senderID = e.target.id; // remember ID of triggering element for resetting focus afterwards
addBox(); // add another box
writeTexts(); // write former inputs back into boxes
document.getElementById(senderID).focus(); // reset focus
} else if (e.target.value.length == 0 && getID(e.target, "event") < getMaxID(boxes, "event")) {
/* box before last box empty -> delete last empty box */
senderID = e.target.id; // remember ID of triggering element for resetting focus afterwards
delBox(); // delete all boxes and create X new boxes
document.getElementById(senderID).focus(); // reset focus
}
}
}
function loadTexts() {
var boxes = document.getElementsByClassName("eventBox");
for (var i=0; i < boxes.length; i++) {
eventTexts[getID(document.getElementById(boxes[i].id), "event")] = boxes[i].value;
}
}
function writeTexts() {
var boxes = document.getElementsByClassName("eventBox");
for (var i=0; i < boxes.length-1; i++) {
document.getElementById(boxes[i].id).value = eventTexts[getID(boxes[i], "event")];
}
}
var eventTexts = new Array();
var senderID;
document.getElementById("event1").addEventListener("input", resizeEventList);
</script>