<script language="javascript">
function aa()
{
if(document.getElementById("text").value=="")
{
document.getElementById("str").innerHTML='不能为空!';
}
else
{
document.getElementById("str").innerHTML='';
}
}
</script>
<form id="form1" name="form1" method="post" action="">
<table width="100%" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="27%"><input type="text" name="text" id="text" onblur="return aa()" /></td>
<td width="73%"><div id="str"></div></td>
</tr>
</table>
</form>
function aa()
{
if(document.getElementById("text").value=="")
{
document.getElementById("str").innerHTML='不能为空!';
}
else
{
document.getElementById("str").innerHTML='';
}
}
</script>
<form id="form1" name="form1" method="post" action="">
<table width="100%" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="27%"><input type="text" name="text" id="text" onblur="return aa()" /></td>
<td width="73%"><div id="str"></div></td>
</tr>
</table>
</form>
在输入框失去焦点时设计那个元素的innerHTML的内容就行了, 可以给这个元素加样式,以突出提示信息...
<form name="form1">
<input type="username" /><span id="myspan"><span>
</form>var username = document.form1.username;username.onblur=function(){
if(this.value == '')document.getElementById('mySpan').innerHTML = '用户名为空或格式不对';
}
function aa()
{
if(document.getElementById("text").value=="")
{
document.getElementById("str").innerHTML='不能为空!';
}
else
{
document.getElementById("str").innerHTML='';
}
}
</script>
<form id="form1" name="form1" method="post" action="">
<table width="100%" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="27%"><input type="text" name="text" id="text" onblur="return aa()" /></td>
<td width="73%"><div id="str"></div></td>
</tr>
</table>
</form>思路就是,失去焦点时发生!!