网页交互与输入限制技巧-优快云博客

本文链接：https://blog.youkuaiyun.com/iteye_15544/article/details/81792739

本文介绍了网页中如何通过JavaScript实现各种输入限制与交互控制，包括禁止使用键盘、限制输入内容类型、设置输入框功能（如只允许数字、IP地址等）、自适应文本行数、上传预览图片等功能。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

http://hi.baidu.com/behony/blog/item/b67843d7ae0484dea144df0f.html

2007-09-12 13:18

ENTER键可以让光标移到下一个输入框

　　只能是中文

　　只能是英文和数字.屏蔽了输入法

　　只能输入英文和数字

　　只能是数字

　　只能显示，不能修改的文本框

　　只能是数字,判断按键代码如下:

　　附：获取键盘的KeyCode

<html>
<head>
<script language="javascript">
    ns4 = (document.layers) ? true : false;
    ie4 = (document.all) ? true : false;
function keyDown(e){
    if(ns4){
    var nkey=e.which;
    var iekey='现在是ns浏览器';
    var realkey=String.fromCharCode(e.which);
}
    if(ie4){
    var iekey=event.keyCode;
    var nkey='现在是ie浏览器';
    var realkey=String.fromCharCode(event.keyCode);
    if(event.keyCode==32){realkey='\' 空格\''}
    if(event.keyCode==13){realkey='\' 回车\''}
    if(event.keyCode==27){realkey='\' Esc\''}
    if(event.keyCode==16){realkey='\' Shift\''}
    if(event.keyCode==17){realkey='\' Ctrl\''}
    if(event.keyCode==18){realkey='\' Alt\''}
}
    alert('ns浏览器中键值:'+nkey+'\n'+'ie浏览器中键值:'+iekey+'\n'+'实际键为'+realkey);
}
document.onkeydown = keyDown;
if(ns4){
document.captureEvents(Event.KEYDOWN);}
</script>
</head>
<body>
//Javascript Document.
<hr>
<center>
<h3>请按任意一个键。。。。</h3>
</center>
</body>
</html>

　　限制网页用键盘

　　限制键盘的某个键：

　　再加个找按键的值

　　只能是IP地址

<html>

<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<style>
.a3
</style>
<script>
function mask(obj){
obj.value=obj.value.replace(/[^\d]/g,'')
key1=event.keyCode
if (key1==37 || key1==39)
{ obj.blur();
nextip=parseInt(obj.name.substr(2,1))
nextip=key1==37?nextip-1:nextip+1;
nextip=nextip>=5?1:nextip
nextip=nextip<=0?4:nextip
eval("ip"+nextip+".focus()")
}
if(obj.value.length>=3)
if(parseInt(obj.value)>=256 || parseInt(obj.value)<=0)
{
alert(parseInt(obj.value)+"IP地址错误！")
obj.value=""
obj.focus()
return false;
}
else
{ obj.blur();
nextip=parseInt(obj.name.substr(2,1))+1
nextip=nextip>=5?1:nextip
nextip=nextip<=0?4:nextip
eval("ip"+nextip+".focus()")
}
}
function mask_c(obj)
{
clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))
}

</script>
<title>IP地址输入</title>

</head>
<body>IP地址输入
<div style="border-width:1;border-color:balck;border-style:solid;width:165;font-size:9pt">
<input type=text name=ip1 maxlength=3 class=a3 onkeyup="mask(this)" onbeforepaste=mask_c()>.
<input type=text name=ip2 maxlength=3 class=a3 onkeyup="mask(this)" onbeforepaste=mask_c()>.
<input type=text name=ip3 maxlength=3 class=a3 onkeyup="mask(this)" onbeforepaste=mask_c()>.
<input type=text name=ip4 maxlength=3 class=a3 onkeyup="mask(this)" onbeforepaste=mask_c()>
</div>
</body>

</html>

　　用#default#savehistory防止后退清空text文本框：

<HTML>
<HEAD>
<META NAME="save" CONTENT="history">
<STYLE>
.saveHistory
</STYLE>
</HEAD>
<BODY>
<INPUT class=saveHistory type=text id=oPersistInput>
<input type=button onclick='javascript:location.href="http://www.webjx.com/"' value='点击进入,再按后退键试试？'>
</BODY>
</HTML>

　　TEXTAREA自适应文字行数的多少

　　上传预览图片

　　去掉下拉选项的边框

<div style="position: absolute; left: 10px; top: 10px; width: 115px; height: 20px;    clip:rect(2 114 20 2);">
     <select>
      <option >cnpeople</option>
      <option >cnrose</option>
     <option >cnbruce</option>
    </select>
    </font>
</div>

　　下拉列表打开窗口

<select onChange="if(this.selectedIndex && this.selectedIndex!=0)this.selectedIndex=0;">
<option selected>更多链接……</option>
<option value="http://www.cnbruce.com">cnbruce</option>
<option value="http://daonet.myrice.com/old/">daonet</option>
<option value="http://www.blueidea.com">blue!dea
</select>

　　TAB的显示

      switch (event.keyCode)
      {
          case (8)      :
              if (!(sel.getClientRects().length > 1))
              {
                  event.returnValue = true
                  return
              }
              code = sel.text
              tmp = sel.duplicate()
              tmp.moveToPoint(r.getBoundingClientRect().left, sel.getClientRects()[0].top)
              sel.setEndPoint("startToStart", tmp)
              sel.text = sel.text.replace(/^\t/gm, "")
              code = code.replace(/^\t/gm, "").replace(/\r\n/g, "\r")
              r.findText(code)
              r.select()
              break
          case (9)      :
              if (sel.getClientRects().length > 1)
              {
                  code = sel.text
                  tmp = sel.duplicate()
                  tmp.moveToPoint(r.getBoundingClientRect().left, sel.getClientRects()[0].top)
                  sel.setEndPoint("startToStart", tmp)
                  sel.text = "\t"+sel.text.replace(/\r\n/g, "\r\t")
                  code = code.replace(/\r\n/g, "\r\t")
                  r.findText(code)
                  r.select()
              }
              else
              {
                  sel.text = "\t"
                  sel.select()
              }
              break
          case (13)      :
              tmp = sel.duplicate()
              tmp.moveToPoint(r.getBoundingClientRect().left, sel.getClientRects()[0].top)
              tmp.setEndPoint("endToEnd", sel)

              for (var i=0; tmp.text.match(/^[\t]+/g) && i<tmp.text.match(/^[\t]+/g)[0].length; i++)      tabs += "\t"
              sel.text = "\r\n"+tabs
              sel.select()
              break
          default          :
              event.returnValue = true
              break
      }
}
</script>

<textarea cols=75 rows=20 onkeydown="editTab()">
<script>
alert("ok")
</script>
</textarea>

　　文本框的上/下拉

<form name="cnbruce">
<textarea name="com">
</textarea>
</form>
<SPAN title='放大输入框' style='FONT-SIZE: 12px; CURSOR: hand' onclick=document.cnbruce.com.rows+=4>向下</SPAN>
<SPAN title='缩小输入框' style='FONT-SIZE: 12px; CURSOR: hand' class='arrow' onclick='if(document.cnbruce.com.rows>=4)document.cnbruce.com.rows-=4;else return false'>向上</SPAN>

　　一个复选框，点击之后一组复选框全部都选上

　　Debug Textarea：在线写 js 脚本的时候，用来即时查错的东西！

<HTML>
<HEAD>
<TITLE>Debug Textarea</TITLE>
<meta http-equiv='Content-Type' content='text/html; charset=gb2312'>
</HEAD>
<style>
* {
      font-size: 12px
}
body {
      margin: 10px; padding: 0px
}
table.list{
      cursor: default;
      border:1px solid #cccccc
      background-color: #cccccc;
      border-collapse: collapse;
      border-Color: #cccccc;
}
</style>
<script language="javascript">
// Coded by windy_sk <windy_sk@126.com> 20040205

function reportError(msg,url,line) {
      var str = "You have found an error as below: \n\n";
      str += "Err: " + msg + " on line: " + line;
      alert(str);
      return true;
}

window.onerror = reportError;

function show_ln(){
      var txt_ln       = document.getElementById('txt_ln');
      var txt_main       = document.getElementById('txt_main');
      txt_ln.scrollTop = txt_main.scrollTop;
      while(txt_ln.scrollTop != txt_main.scrollTop) {
          txt_ln.value += (i++) + '\n';
          txt_ln.scrollTop = txt_main.scrollTop;
      }
      return;
}

function editTab(){
      var code, sel, tmp, r
      var tabs=''
      event.returnValue = false
      sel =event.srcElement.document.selection.createRange()
      r = event.srcElement.createTextRange()

      switch (event.keyCode){
          case (8)      :
              if (!(sel.getClientRects().length > 1)){
                  event.returnValue = true
                  return
              }
              code = sel.text
              tmp = sel.duplicate()
              tmp.moveToPoint(r.getBoundingClientRect().left, sel.getClientRects()[0].top)
              // 出错检验代码~~~~~~
              if(sel.parentElement() != tmp.parentElement()) return;
              sel.setEndPoint('startToStart', tmp)
              sel.text = sel.text.replace(/^\t/gm, '')
              code = code.replace(/^\t/gm, '').replace(/\r\n/g, '\r')
              r.findText(code)
              r.select()
              break
          case (9)      :
              if (sel.getClientRects().length > 1){
                  code = sel.text
                  tmp = sel.duplicate()
                  tmp.moveToPoint(r.getBoundingClientRect().left, sel.getClientRects()[0].top)
                  // 出错检验代码~~~~~~
                  if(sel.parentElement() != tmp.parentElement()) return;
                  sel.setEndPoint('startToStart', tmp)
                  sel.text = '\t'+sel.text.replace(/\r\n/g, '\r\t')
                  code = code.replace(/\r\n/g, '\r\t')
                  r.findText(code)
                  r.select()
              }else{
                  sel.text = '\t'
                  sel.select()
              }
              break
          case (13)      :
              tmp = sel.duplicate()
              tmp.moveToPoint(r.getBoundingClientRect().left, sel.getClientRects()[0].top)
              // 出错检验代码~~~~~~
              if(sel.parentElement() != tmp.parentElement()) return;
              tmp.setEndPoint('endToEnd', sel)
              for (var i=0; tmp.text.match(/^[\t]+/g) && i<tmp.text.match(/^[\t]+/g)[0].length; i++)      tabs += '\t'
              sel.text = '\r\n'+tabs
              sel.select()
              break
          default          :
              event.returnValue = true
              break;
      }
      return;
}

function runcode() {
      var str = document.getElementById("txt_main").value;
      var code_win = window.open('about:blank');
      code_win.document.open();
      code_win.document.writeln("<script>");
      code_win.document.writeln("function reportError(msg,url,line){\nline-=14;\nvar str='You have found an error as below: \\n\\n';\nstr+='Err: '+msg+' on line: '+(line);\nalert(str);\nopener.goto(line);\nopener.focus();\nwindow.onerror=null;\nsetTimeout('self.close()',10);\nreturn true;\n}");
      code_win.document.writeln("window.onerror = reportError;");
      code_win.document.writeln("<\/script>");
      code_win.document.writeln(str);
      code_win.document.close();
      return;
}

function savecode() {
      var str = document.getElementById("txt_main").value;
      var code_win = window.open('about:blank','_blank','top=10000');
      code_win.document.open();
      code_win.document.writeln(str);
      code_win.document.close();
      code_win.document.execCommand('saveas','','code.html');
      code_win.close();
      return;
}

window.onload = function() {document.getElementById("txt_main").value = "<script>\nalert(')\n<\/script>";}
</script>
<BODY>
<table width='600' class='list' border='1' bgcolor='#eeeeee' bordercolorlight='#000000' bordercolordark='#FFFFFF' cellpadding='0' cellspacing='0'>
    <tr bgcolor='#cccccc'>
      <td colspan='2' height='20' align='center'><b>Debug Textarea</b></td>
    </tr>
    <tr>
      <td colspan='2'>
          <table width='95%' border='0' align='center' >
        <tr>
          <td align='center'><br />
            <textarea id='txt_ln' name='content' rows='10' style='width:40px;overflow:hidden;height:200px;border-right:0px;text-align:right;line-height:14px' onselectstart='this.nextSibling.focus();return false' readonly></textarea><textarea id='txt_main' name='content' rows='10' cols='80' onkeydown='editTab()' onkeyup='show_ln()' onscroll='show_ln()' wrap='off' style='overflow:auto;height:200px;padding-left:5px;border-left:0px;line-height:14px'></textarea>
            <script>for(var i=1; i<=20; i++) document.getElementById('txt_ln').value += i + '\n';</script>
          </td>
        </tr>
            <tr>
              <td align='center'><br />
                <input type='button' value=' 运行 ' onclick='runcode()' accesskey='r'>  
                <input type='button' value=' 保存 ' onclick='savecode()' accesskey='s'>  
                <input type='button' value=' 跳转 ' onclick="goto(prompt('Please input the line number', '1'))"    accesskey='g'>  
              </td>
            </tr>
          </table>
      </td>
    </tr>
</table>
</BODY>
</HTML>

常用JS代码集