<html>
<head lang="en">
<meta charset="UTF-8">
<script src="http://code.jquery.com/jquery-1.11.2.js"></script>
</head>
<body>
<input type="text" id="ff"/>
<script>
function setNunFun(ctrName) {
var ctrlName = $('#' + ctrName);
ctrlName.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 () {
setNunFun('ff')
})
</script>
</body>
</html>