JAVASCRIPT验证大全（转载）
<script language="javascript">
<!--
function form1_onsubmit()
{
var urlreg=/^[A-Za-z0-9]+\.[A-Za-z0-9]+[\/=\?%\-&_~`@[\]\':+!]*([^<>\"\"])*$/
var url=document.form1.url.value
if (!urlreg.test(url))
    {
      alert("网址错误！")
      document.form1.url.focus()
      return false
     } 
}
-->
</script>
<form name="form1" method="post" action="" onsubmit="return form1_onsubmit()">
http://<input type="text" name="url" value="">
<input type="submit" name="submit" value="验证">
</form>

javascript验证表单大全
1. 长度限制
<script>
function test()
{
if(document.a.b.value.length>50)
{
alert("不能超过50个字符！");
document.a.b.focus();
return false;
}
}
</script>
<form name=a onsubmit="return test()">
<textarea name="b" cols="40" wrap="VIRTUAL" rows="6"></textarea>
<input type="submit" name="Submit" value="check">
</form>

2. 只能是汉字
<input onkeyup="value="/oblog/value.replace(/[^\u4E00-\u9FA5]/g,'')">

3." 只能是英文
<script language=javascript>
function onlyEng()
{
if(!(event.keyCode>=65&&event.keyCode<=90))
event.returnvalue=false;
}
</script>

<input onkeydown="onlyEng();">

4. 只能是数字
<script language=javascript>
function onlyNum()
{
if(!((event.keyCode>=48&&event.keyCode<=57)||(event.keyCode>=96&&event.keyCode<=105)))
//考虑小键盘上的数字键
event.returnvalue=false;
}
</script>

<input onkeydown="onlyNum();">

5. 只能是英文字符和数字
<input onkeyup="value="/oblog/value.replace(/[\W]/g,"'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))">

6. 验证油箱格式
<SCRIPT LANGUAGE=javascript RUNAT=Server>
function isEmail(strEmail) {
if (strEmail.search(/^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/) != -1)
return true;
else
alert("oh");
}
</SCRIPT>
<input type=text onblur=isEmail(this.value)>

7. 屏蔽关键字(这里屏蔽***和****)
<script language="javascript1.2">
function test() {
if((a.b.value.indexOf ("***") == 0)||(a.b.value.indexOf ("****") == 0)){
alert(":)");
a.b.focus();
return false;}
}
</script>
<form name=a onsubmit="return test()">
<input type=text name=b>
<input type="submit" name="Submit" value="check">
</form>

8. 两次输入密码是否相同
<FORM METHOD=POST ACTION="">
<input type="password" id="input1">
<input type="password" id="input2">
<input type="button" value="test" onclick="check()">
</FORM>
<script>
function check()
{
with(document.all){
if(input1.value!=input2.value)
{
alert("false")
input1.value = "";
input2.value = "";
}
else document.forms[0].submit();
}
}
</script>
够了吧
屏蔽右键 很酷
oncontextmenu="return false" ondragstart="return false" onselectstart="return false"
加在body中


二

2.1   表单项不能为空

<script   language="javascript">
<!--
function   CheckForm()
{ 
if   (document.form.name.value.length   ==   0)   { 
alert("请输入您姓名!");
document.form.name.focus();
return   false;
}
return   true;