js实现input中输入数字，控制每四位加一个空格（银行卡号格式）
转自：http://www.haorooms.com/post/js_yinghangkahao
前言
今天来讲讲js中实现input中输入数字，控制每四位加一个空格的方法！这个主要是应用于我们在填写表单的时候，填写银行卡信息，要求我们输入的数字是四位一个空格！今天主要介绍两种方式来实现这个方法！但是都运用到了键盘码。下面我就列举一下键盘码，以备后面查阅！
键盘各按键对应的数字
keycode 8 = BackSpace | keycode 9 = Tab | keycode 12 = Clear keycode 13 = Enter | keycode 16 = Shift | keycode 17 = Control keycode 18 = Alt | keycode 19 = Pause | keycode 20 = CapsLock keycode 27 = Escape | keycode 32 = Space | keycode 33 = Prior
keycode 34 = Next | keycode 35 = End | keycode 36 = Home keycode 37 = Left | keycode 38 = Up | keycode 39 = Right keycode 40 = Down | keycode 41 = Select | keycode 42 = Print keycode 43 = Execute | keycode 45 = Insert | keycode 46 = Delete keycode 47 = Help | keycode 48 = 0 | keycode 49 = 1 keycode 50 = 2 | keycode 51 = 3 | keycode 52 = 4 keycode 53 = 5 | keycode 54 = 6 | keycode 55 = 7 keycode 56 = 8 | keycode 57 = 9 | keycode 65 = A keycode 66 = B | keycode 67 = C | keycode 68 = D keycode 69 = E | keycode 70 = F | keycode 71 = G keycode 72 = H | keycode 73 = I | keycode 74 = J keycode 75 = K | keycode 76 = L | keycode 77 = M keycode 96 = KP_0 | keycode 97 = KP_1 | keycode 98 = KP_2 keycode 99 = KP_3 | keycode 100 = KP_4 | keycode 101 = KP_5 keycode 102 = KP_6 | keycode 103 = KP_7 | keycode 104 = KP_8 keycode 105 = KP_9 | keycode 78 = N | keycode 79 = O keycode 80 = P | keycode 81 = Q | keycode 82 = R keycode 83 = S | keycode 84 = T | keycode 85 = U keycode 86 = V | keycode 87 = W | keycode 88 = X keycode 89 = Y | keycode 90 = Z | keycode 112 = F1 keycode 113 = F2 | keycode 114 = F3 | keycode 115 = F4 keycode 116 = F5 | keycode 117 = F6 | keycode 118 = F7 keycode 119 = F8 | keycode 120 = F9 | keycode 121 = F10 keycode 122 = F11
96到105是小键盘数字键！48到57是大键盘的数字键！
注意：上面的键盘代码是keydown或者keyup按下的代码！是按键的映射代码。
keypress键盘按下去有些是不一样的！因为keypress是输入字符的Unicode。
感兴趣的可以去测试一下：
<input type="text" size="50" onkeypress="uniCharCode(event)" onkeydown="uniKeyCode(event)">
<p>onkeypress - <span id="demo"></span></p>
<p>onkeydown - <span id="demo2"></span></p>
<script>
function uniCharCode(event) {
var char = event.which || event.keyCode;
document.getElementById("demo").innerHTML = " Unicode 字符代码为: " + char;
}
function uniKeyCode(event) {
var key = event.keyCode;
document.getElementById("demo2").innerHTML = " Unicode 键代码为: " + key;
}
</script>
实现方法一
<input type="text" id="haorooms"/>
<script src="http://www.haorooms.com/theme/assets/js/jquery.js"></script>
!function () {
$('#haorooms').on('keyup mouseout input',function(e){
if((e.which >= 48 && e.which <= 57) ||(e.which >= 96 && e.which <= 105 )){
var $this = $(this),
v = $this.val();
/\S{5}/.test(v) && $this.val(v.replace(/\s/g,'').replace(/(.{4})/g, "$1 "));
}
});
}();
上面的方式我们可以用js来实现，代码如下：
!function () {
document.getElementById('haorooms').onkeyup = function (event) {
if((event.which >= 48 && event.which <= 57) ||(event.which >= 96 && event.which <= 105 )){
var v = this.value;
if(/\S{5}/.test(v)){
this.value = v.replace(/\s/g, '').replace(/(.{4})/g, "$1 ");
}
};
}
}();
方法一解释
上面主要是运用了一些正则表达式，关于正则表达式，记得不是很牢的同学可以查看：http://www.haorooms.com/post/js_regex_refuse
上面的自调用匿名函数我之前文章中也提及过！http://www.haorooms.com/post/js_jquery_chajian 及http://www.haorooms.com/post/qianduan_xnyhbc 等等很多文章提及过！下面我们一起再来复习一下！
我们可以这么写！
(function(){
})()当然也可以如下写：
!function(){}();
+function(){}();
-function(){}();
~function(){}();
~(function(){})();
void function(){}();
(function(){}());
方法二
另外一种方法可以如下写：
$(function() {
$('#haorooms').on('keyup', function(e) {
//只对输入数字时进行处理
if((e.which >= 48 && e.which <= 57) ||
(e.which >= 96 && e.which <= 105 )){
//获取当前光标的位置
var caret = this.selectionStart
//获取当前的value
var value = this.value
//从左边沿到坐标之间的空格数
var sp = (value.slice(0, caret).match(/\s/g) || []).length
//去掉所有空格
var nospace = value.replace(/\s/g, '')
//重新插入空格
var curVal = this.value = nospace.replace(/(\d{4})/g, "$1 ").trim()
//从左边沿到原坐标之间的空格数
var curSp = (curVal.slice(0, caret).match(/\s/g) || []).length
//修正光标位置
this.selectionEnd = this.selectionStart = caret + curSp - sp
}
})
})
$(function() {}）这个是$(document).ready(function(){})的简写！
