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怎样验证我当前的Text框是否为空？
我原先的做法就是把form提交后再检查上一个页面的某个框是否为空，能否在我点击提交按钮的时候立即检查当前输入框是否为空，并且弹出一个提示框
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zhuyuantan 2002-08-01
form 表单里面有个 onsubmit="return function()" 的东东
return false 和return true 表示该 function() 返回真或假
如果返回真就执行 form 表单的 action 动作, 返回假就不执行 action 动作
return false 和return true 表示该 function() 返回真或假
如果返回真就执行 form 表单的 action 动作, 返回假就不执行 action 动作
huang_2 2002-08-01
return false 和 return true 分别起什么作用？
huang_2 2002-08-01
太感动了，这么多热心人
JavaCoffee 2002-08-01
<input type="text" name="txttest" size="20" onblur="if (this.value=='') alert('不能为空！');">
MeXP 2002-08-01
更正
<html>
<head>
<title>test</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<script language=javascript>
function checkdata()
{
if (form1.aaa.value=="")
{
form1.aaa.focus();
alert("Please input");
return false;
}
else
return true;
}
</script>
</head>
<body bgcolor="#FFFFFF" text="#000000" >
<form name="form1" method="post" action="" onsubmit="return checkdata()">
<input type="text" name="aaa" >
<input type="submit" name="Submit" value="Submit">
</form>
</body>
</html>
<html>
<head>
<title>test</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<script language=javascript>
function checkdata()
{
if (form1.aaa.value=="")
{
form1.aaa.focus();
alert("Please input");
return false;
}
else
return true;
}
</script>
</head>
<body bgcolor="#FFFFFF" text="#000000" >
<form name="form1" method="post" action="" onsubmit="return checkdata()">
<input type="text" name="aaa" >
<input type="submit" name="Submit" value="Submit">
</form>
</body>
</html>
yhncom_36de 2002-08-01
给你一个例子，很实用的，可要给分呀！把代码粘贴后运行:代码如下：
<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">
<title>New Page 1</title>
</head>
<body>
<script Language="JavaScript" Type="text/javascript"><!--
function FrontPage_Form1_Validator(theForm)
{
if (theForm.username.value=="")
{
alert("请输入用户名！");
theForm.username.focus();
return (false);
}
return (true);
}
//--></script>
<table cellpadding=0 cellspacing=1 border=0 align=center>
</table>
<form method="POST" action="file:///C:/Inetpub/wwwroot/web/addok.asp" onsubmit="return FrontPage_Form1_Validator(this)" name="FrontPage_Form1" language="JavaScript">
<table border=1 cellspacing=0 width=750 height="12" style="border-collapse: collapse" bordercolor="#111111" cellpadding="0">
<tr>
<td class=p2 align=right width="167" height="1"><font color=FF9933>*</font>用户名</td>
<td class=p2 align=right width="6" height="1"> </td>
<td bgcolor=E5E6D3 width="7" height="1"> </td>
<td bgcolor=E5E6D3 width="241" height="1"><b>
<input name=username size=25 type=text maxlength=14 style="font-size: 12px"></b></td>
<td class=p2 bgcolor=E5E6D3 nowrap width="313" height="1">用户名最多为10个字符或数字</td>
</tr>
</table>
<hr align=center noshade width=100% color=black>
<p align="center"><input type="submit" value="提交" name="B1"> <input type="reset" value="重写" name="B2"></p>
</form>
</body>
</html>
<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">
<title>New Page 1</title>
</head>
<body>
<script Language="JavaScript" Type="text/javascript"><!--
function FrontPage_Form1_Validator(theForm)
{
if (theForm.username.value=="")
{
alert("请输入用户名！");
theForm.username.focus();
return (false);
}
return (true);
}
//--></script>
<table cellpadding=0 cellspacing=1 border=0 align=center>
</table>
<form method="POST" action="file:///C:/Inetpub/wwwroot/web/addok.asp" onsubmit="return FrontPage_Form1_Validator(this)" name="FrontPage_Form1" language="JavaScript">
<table border=1 cellspacing=0 width=750 height="12" style="border-collapse: collapse" bordercolor="#111111" cellpadding="0">
<tr>
<td class=p2 align=right width="167" height="1"><font color=FF9933>*</font>用户名</td>
<td class=p2 align=right width="6" height="1"> </td>
<td bgcolor=E5E6D3 width="7" height="1"> </td>
<td bgcolor=E5E6D3 width="241" height="1"><b>
<input name=username size=25 type=text maxlength=14 style="font-size: 12px"></b></td>
<td class=p2 bgcolor=E5E6D3 nowrap width="313" height="1">用户名最多为10个字符或数字</td>
</tr>
</table>
<hr align=center noshade width=100% color=black>
<p align="center"><input type="submit" value="提交" name="B1"> <input type="reset" value="重写" name="B2"></p>
</form>
</body>
</html>
meizz 2002-08-01
<form onsubmit="return cc()">
<input type=text name=tt>
<input type=submit value=ok></form>
<script language=javascript>
function cc()
{
if (document.all.tt.value=="")
{
alert("输入框不能为空");
document.all.tt.focus();
return false;
}
return true;
}
</script>
<input type=text name=tt>
<input type=submit value=ok></form>
<script language=javascript>
function cc()
{
if (document.all.tt.value=="")
{
alert("输入框不能为空");
document.all.tt.focus();
return false;
}
return true;
}
</script>
ChinaOk 2002-08-01
看看faq
grooving 2002-08-01
javascript:
function check(){
if(document.form1.textbox1.value.length==0){
alert("空");
return false;
}
retrun true;
}
在onsumit事件里return check();
function check(){
if(document.form1.textbox1.value.length==0){
alert("空");
return false;
}
retrun true;
}
在onsumit事件里return check();
jhlcss 2002-08-01
If trim(document.all("txtname").value)="" Then
msgbox "不能为空"
End If
msgbox "不能为空"
End If
MeXP 2002-08-01
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<script language=javascript>
function checkdata()
{
if (form1.aaa.value="")
{
form1.bbb.focus();
alert("Please input");
return false;
}
else
return true;
}
</script>
</head>
<body bgcolor="#FFFFFF" text="#000000" >
<form name="form1" method="post" action="" onsubmit="return checkdata()">
<input type="text" name="aaa" >
</form>
</body>
</html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<script language=javascript>
function checkdata()
{
if (form1.aaa.value="")
{
form1.bbb.focus();
alert("Please input");
return false;
}
else
return true;
}
</script>
</head>
<body bgcolor="#FFFFFF" text="#000000" >
<form name="form1" method="post" action="" onsubmit="return checkdata()">
<input type="text" name="aaa" >
</form>
</body>
</html>
jo_yoko 2002-08-01
<HTML>
<head>
<script language="javascript">
function check()
{
if (form1.txt.value=="")
{
alert("不得为空");
return false;
}
else
form1.submit();
}
</script>
</head>
<body>
<form name="form1" action="???.asp">
<input type="text" name="txt" ><br>
<input type="button" name="btn" onclick="check();">
</form>
</body>
</HTML>
<head>
<script language="javascript">
function check()
{
if (form1.txt.value=="")
{
alert("不得为空");
return false;
}
else
form1.submit();
}
</script>
</head>
<body>
<form name="form1" action="???.asp">
<input type="text" name="txt" ><br>
<input type="button" name="btn" onclick="check();">
</form>
</body>
</HTML>