js控制输入只能是数字

一般都是通过正则表达式进行判断的。下面是简单的代码实现。仅供参考：

1.文本框只能输入数字代码(小数点也不能输入)

<input onkeyup="this.value=this.value.replace(/\D/g,'')" onafterpaste="this.value=this.value.replace(/\D/g,'')">

 

2.只能输入数字,能输小数点.

<input onkeyup="if(isNaN(value))execCommand('undo')" onafterpaste="if(isNaN(value))execCommand('undo')">

<input name=txt1 onchange="if(/\D/.test(this.value)){alert('只能输入数字');this.value='';}">

 

3.数字和小数点方法二

<input type=text t_value="" o_value="" 

onkeypress="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"; 

        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}">