input输入字符限制

---

只读文本框内容,只能显示，不能修改

readonly value="只能显示，不能修改">

---

只能是中文(有闪动)

<input onkeyup="value=value.replace(/[ -~]/g,'')">

---

只能输入英文和数字(有闪动)

"value=value.replace(/[\W]/g,'')"
       onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))">

---

只能是数字，整数(有闪动)

"value=value.replace(/[^\d]/g,'') "
       onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))">

---

只能是数字，整数(无闪动)

type="text"
       onkeypress='return /^\d$/.test(String.fromCharCode(event.keyCode||event.keycode||event.which))'
       oninput='this.value = this.value.replace(/\D+/g, "")'
       onpropertychange='if(!/\D+/.test(this.value)){return;};this.value=this.value.replace(/\D+/g, "")'
       onblur='this.value = this.value.replace(/\D+/g, "")'/>

---

只能输入数字和小数点、负数(有闪动)

[\+\-]?\d*?\.?\d*?$/))this.value=this.t_value;else this.t_value=this.value;if(this.value.match(/^(?:[\+\-]?\d+(?:\.\d+)?)?$/))this.o_value=this.value"
       onkeyup="if(!this.value.match(/^[\+\-]?\d*?\.?\d*?$/))this.value=this.t_value;else this.t_value=this.value;if(this.value.match(/^(?:[\+\-]?\d+(?:\.\d+)?)?$/))this.o_value=this.value"
       onblur="if(!this.value.match(/^(?:[\+\-]?\d+(?:\.\d+)?|\.\d*?)?$/))this.value=this.o_value;else{if(this.value.match(/^\.\d+$/))this.value=0+this.value;if(this.value.match(/^\.$/))this.value=0;this.o_value=this.value}">

---

js控制 只能输入数字、小数点、负数(有闪动)

<input name="input" type="text" onkeyup="JHshNumberText(this)" id="title">
<script language="javascript" type="text/javascript">
  function JHshNumberText(a) {
    var fa = "";
    if (a.value.substring(0, 1) == "-")
      fa = "-";

    var str = (a.value.replace(/[^0-9.]/g, '')).replace(/[.][0-9]*[.]/, '.');

    if (str.substring(0, 1) == ".")
      str = "0" + str;
    a.value = fa + str;

  }
script>

---

不能输入数字(有闪动)

"value=value.replace(/[\d]/g,'') "
       onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[\d]/g,''))"
       name="Numbers">

---

只能输入英文字母和数字,不能输入中文和符号(有闪动)

[^\w\.\/]/ig,'')">

---

只能输入数字和指定英文chun(有闪动)

<input onKeyUp="value=value.replace(/[^\d|chun]/g,'')">

---