关于一个最简单的输入限制

Question

if(len(document.getElementById("servername").value)>16)
{
alert("不能超过16个字符");
}
/* 
用途：检查输入字符串是否只由汉字、字母、数字组成 
输入： 
value：字符串 
返回： 
如果通过验证返回true,否则返回false 
*/ 
function f_check_ZhOrNumOrLett(obj){    //判断是否是汉字、字母、数字组成   
    var regu = "^[0-9a-zA-Z\u4e00-\u9fa5]+$";      
    var re = new RegExp(regu);   
    if (re.test( obj.value )) {   
      return true;   
    }   
    return false;   
}   

Answer 1

用正则/^[\w\u4e00-\u9fa5]{0,16}$/.test(this.value)<FORM name="admin" method="post" action="xitongok.php" onsubmit="return check()">
              <td height="125" ><table width="92%" height="73" border="0" align="center" cellpadding="0" cellspacing="0" >
                <tr>
                  <td width="52%" height="24" align="right" >&nbsp;
                      <input name="r1" type="radio" value="0" id="dhcp1"  onclick="change(true)"  <?php if ($dhcp=='1') echo 'checked="checked"';?>>
                    启用DHCP</td>
                  <td align="center" >&nbsp;
                      <input name="r1" type="radio" value="1" id="dhcp2"  onclick="change(false)" <?php if ($dhcp=='0') echo 'checked="checked"';?> >
                    不启用DHCP</td>                </tr>
  <td colspan="2"><table width="100%" border="0" cellpadding="0" cellspacing="0" id="con">
    <tr>
      <td width="52%" height="24" align="right" >IP地址：</td>
      <td width="48%" align="left" ><input name="ip" type="text"  id="ip" value="<?php echo $ip?>" onKeydown="return check1(event)" <?php if ($dhcp=='1') echo "readOnly = 'readonly'";?>/></td>
    </tr>
    <tr>
      <td width="52%" height="24" align="right" >子网掩码：</td>
      <td width="48%" align="left" ><input name="netmask" type="text"  id="netmask" value="<?php echo $netmask?>"  onKeydown="return check2(event)" <?php if ($dhcp=='1') echo "readOnly = 'readonly'";?>/></td>
    </tr>
    <tr>
      <td width="52%" height="24" align="right" >默认网关：</td>
      <td width="48%" align="left" ><input name="gateway" type="text"  id="gateway" value="<?php echo $gateway?>"  onKeydown="return check1(event)" <?php if ($dhcp=='1') echo "readOnly = 'readonly'";?>/></td>
    </tr>
  </table></td><tr>
    <td width="52%" height="24" align="right" >服务器别名：</td>
    <td align="left" ><input name="servername" type="text" id="servername" onblur="alert(/^[\w\u4e00-\u9fa5]{0,16}$/.test(this.value))" value="<?php $servername = iconv("utf-8",'gb2312',$servername); echo $servername;?>" /></td>
  </tr>
              </table>
              <table width="87%" height="24" border="0" align="center" cellpadding="0" cellspacing="1">
                    <tr>
                      <td height="25" align="center" ><input name="tijiao" type="submit" class="btn"  value="确　定" >&nbsp;                        </td>
                    </tr>
                </table></td></FORM>

Answer 2

当返回true的时候怎么才能提交呀？

Answer 3

返回true的时候就提交了啊
因为是onsubmit动作
如果 return false  就表示不执行 submit动作
true的话 就执行了啊

Answer 4

试试
function check(){
    if(document.getElementById("dhcp1").checked)
        return true;    var result = true;
    var ip = document.admin.ip.value;
    result = result && validate(ip);
    var mask = document.admin.netmask.value;
    result = result && validate(mask);
    var gateway = document.admin.gateway.value;
    result = result && validate(gateway);    if(!result){
        alert("请正确填写");
    }
    return result;
}