问题描述
我想为接受日期的文本input
字段实现掩码.屏蔽的值应直接显示在input
内部.
I would like to implement a mask for a text input
field which accepts a date. The masked value should display directly inside of the input
.
类似这样的东西:
<input type='text' value='____/__/__'>
在该示例中,我将掩码写为值,但是我的目的是允许人们写日期而无需键入/
或-
来分隔月份,年份和日期.用户应该能够在显示的字段中输入数字,而掩码会在用户键入时自动强制采用格式.
I wrote the mask as a value in that example, but my intent is to allow people to write a date without typing /
or -
to separate months, years and days. The user should be able to enter numbers into the displayed field, while the mask enforces the format automatically as the user types.
我在其他站点上也看到过这种行为,但是我不知道它是如何工作的或如何自己实现.
I have seen this behavior on other sites, but I have no idea how it works or how to implement it myself.
推荐答案
可以使用 keyup
事件,而 HTMLInputElement
value
,selectionStart
和selectionEnd
属性.这是一个非常简单的实现,可以完成您想要的一些事情.它当然不是完美的,但是可以很好地演示该原理:
Input masks can be implemented using a combination of the keyup
event, and the HTMLInputElement
value
, selectionStart
, and selectionEnd
properties. Here's a very simple implementation which does some of what you want. It's certainly not perfect, but works well enough to demonstrate the principle:
Array.prototype.forEach.call(document.body.querySelectorAll("*[data-mask]"), applyDataMask);
function applyDataMask(field) {
var mask = field.dataset.mask.split('');
// For now, this just strips everything that's not a number
function stripMask(maskedData) {
function isDigit(char) {
return /\d/.test(char);
}
return maskedData.split('').filter(isDigit);
}
// Replace `_` characters with characters from `data`
function applyMask(data) {
return mask.map(function(char) {
if (char != '_') return char;
if (data.length == 0) return char;
return data.shift();
}).join('')
}
function reapplyMask(data) {
return applyMask(stripMask(data));
}
function changed() {
var oldStart = field.selectionStart;
var oldEnd = field.selectionEnd;
field.value = reapplyMask(field.value);
field.selectionStart = oldStart;
field.selectionEnd = oldEnd;
}
field.addEventListener('click', changed)
field.addEventListener('keyup', changed)
}
ISO Date: <input type="text" value="____-__-__" data-mask="____-__-__"/><br/>
Telephone: <input type="text" value="(___) ___-____" data-mask="(___) ___-____"/><br/>
还有许多执行此功能的库.一些示例包括:
There are also a number of libraries out there which perform this function. Some examples include:
- jquery.inputmask
- 屏蔽输入插件
- Politespace (表示输入掩码的替代方法)
- jquery.inputmask
- MASKED INPUT PLUGIN
- Politespace (presents an alternative to input masks)
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