判断输入框输入的是否是数字，不是则阻止提交

<%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
<%
 String path = request.getContextPath();
 String basePath = request.getScheme() + "://"
   + request.getServerName() + ":" + request.getServerPort()
   + path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
  <base href="<%=basePath%>">

  <title>提交前判断输入框是否是数字，不是终止提交</title>
  <script type="text/javascript">
  
  function chkForm(form)
 {
   alert('') ;
  var value = form.d1.value;
  var len = value.length;
  for(var i=0;i<len;i++)
  {
   if(value.charAt(i)>"9" || value.charAt(i)<"0")
   {
    alert("含有非数字字符");     
    return false;
   }
  }
  return true;
 }
  </script>
  </head>
 
  <body>
 
    <form onsubmit="return chkForm(this);">
  <input type="text" name="d1"/>
  <input type="submit"/>
 </form>

  </body>
</html>

 

 

 

 

 

判断输入框输入的是不是全部都是数字

 

<%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
<%
 String path = request.getContextPath();
 String basePath = request.getScheme() + "://"
   + request.getServerName() + ":" + request.getServerPort()
   + path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
  <base href="<%=basePath%>">

  <title>检查输入框输入的是否都是数字</title>

  <script type="text/javascript">

function chkNumber(eleText) {
 var value = eleText.value;
 var len = value.length;
 for ( var i = 0; i < len; i++) {
  if (value.charAt(i) > "9" || value.charAt(i) < "0") {
   alert("含有非数字字符");
   eleText.focus();
   break;
  }
 }
}
</script>

 </head>

 <body>
  <center>

   <input type="text" id="d1" onblur=" chkNumber (this)" />

  </center>
 </body>
</html>

 

<%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
<%
 String path = request.getContextPath();
 String basePath = request.getScheme() + "://"
   + request.getServerName() + ":" + request.getServerPort()
   + path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
  <base href="<%=basePath%>">

  <title>检查输入框输入的是否都是数字</title>

  <script type="text/javascript">

function chkNumber(eleText) {
 var value = eleText.value;
 var len = value.length;
 for ( var i = 0; i < len; i++) {
  if (value.charAt(i) > "9" || value.charAt(i) < "0") {
   alert("含有非数字字符");
   eleText.focus();
   break;
  }
 }
}
</script>

 </head>

 <body>
  <center>

   <input type="text" id="d1" onblur=" chkNumber (this)" />

  </center>
 </body>
</html>