Example of how to control input format in html

<input type="text" onkeyup="this.value=this.value.replace(/[^\u4e00-\u9fa5]/g,&#39;&#39;)">

<input type="text" onkeyup="this.value=this.value.replace(/[^a-zA-Z]/g,&#39;&#39;)">

<input onkeyup="this.value=this.value.replace(/\D/g,&#39;&#39;)" onafterpaste="this.value=this.value.replace(/\D/g,&#39;&#39;)">

方法一：<input onkeyup="if(isNaN(value))execCommand(&#39;undo&#39;)" onafterpaste="if(isNaN(value))execCommand(&#39;undo&#39;)">  
方法二：<input name=txt1 onchange="if(/\D/.test(this.value)){alert(&#39;只能输入数字&#39;);this.value=&#39;&#39;;}">  
方法三：<input onkeyup="this.value=this.value.replace(/[^\d.]/g,&#39;&#39;)" onafterpaste="this.value=this.value.replace(/[^\d.]/g,&#39;&#39;)" >

<input onKeyUp="value=value.replace(/[^\d|chun]/g,&#39;&#39;)">

<input onkeyup="value=value.replace(/[\d]/g,&#39;&#39;) "onbeforepaste="clipboardData.setData(&#39;text&#39;,clipboardData.getData(&#39;text&#39;).replace(/[\d]/g,&#39;&#39;))"   
 maxlength=10 name="Numbers">

<input onkeyup="value=value.replace(/[^\w\.\/]/ig,&#39;&#39;)">

<input type="text" size="20" onkeyup="this.value=this.value.replace(/[^\w_]/g,&#39;&#39;);">

<input type="text" size="20" onkeyup="this.value=this.value.replace(/[^\d-]/g,&#39;&#39;)" onafterpaste="this.value=this.value.replace(/[^\d-]/g,&#39;&#39;)">

<input type="text" size="20" onkeyup="this.value=this.value.replace(/[^a-z0-9_]/g,&#39;&#39;);">

<input type="text" onkeyup="value=value.replace(/[^\d.]/g,&#39;&#39;)">