达到 maxlength 值后关注下一个输入
前一个输入达到其最大长度值后，如何聚焦下一个输入?
How can I focus the next input once the previous input has reached its maxlength value?
a: <input type="text" maxlength="5" />
b: <input type="text" maxlength="5" />
c: <input type="text" maxlength="5" />
如果用户粘贴的文本大于最大长度，理想情况下它应该溢出到下一个输入中.
If a user pastes text that is greater than the maxlength, ideally it should spill into the next input.
jsFiddle: http://jsfiddle.net/4m5fg/1/
我必须强调我不想使用插件，因为我更愿意学习其背后的逻辑，而不是使用已经存在的东西.感谢理解.
I must stress that I do not want to use a plugin, as I'd much rather learn the logic behind this, than use something that already exists. Thanks for understanding.
推荐答案
没有使用 jQuery 并且是一个非常干净的实现:
No jQuery used and is a very clean implementation:
- 从 maxlength 属性中读取.
- 可扩展到容器内任意数量的输入.
- 自动查找下一个要关注的输入.
- 没有 jQuery.
http://jsfiddle.net/4m5fg/5/
<div class="container">
a: <input type="text" maxlength="5" />
b: <input type="text" maxlength="5" />
c: <input type="text" maxlength="5" />
</div>
..
var container = document.getElementsByClassName("container")[0];
container.onkeyup = function(e) {
var target = e.srcElement || e.target;
var maxLength = parseInt(target.attributes["maxlength"].value, 10);
var myLength = target.value.length;
if (myLength >= maxLength) {
var next = target;
while (next = next.nextElementSibling) {
if (next == null)
break;
if (next.tagName.toLowerCase() === "input") {
next.focus();
break;
}
}
}
// Move to previous field if empty (user pressed backspace)
else if (myLength === 0) {
var previous = target;
while (previous = previous.previousElementSibling) {
if (previous == null)
break;
if (previous.tagName.toLowerCase() === "input") {
previous.focus();
break;
}
}
}
}
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