Question

asp中用javascript如何实现必填项验证

效果如以下网址http://citycolor.upo.gov.cn/SurveyAdmin/DoSurvey.asp?Surveyid=18
波迪说的那种方法我会了，我要实现的是网址上那种，因为我这个调查页面本身是从后台随意添加数据自动生成的 ，前台添加数据时要验证。

Answer 1

<script language="javascript">
String.prototype.trim=trim;
function trim() {
return this.replace(/^\s+|\s+$/g, "");
}

function submitForm() {
var form=document.forms("frmMain");
if(validate(form))
form.submit();
return false;
}
function validate(form) {
var fieldCount=parseInt(form.fieldCount.value);
var fieldType, fieldName,fieldForce;
for(var i=1;i<=fieldCount; i++) {
fieldType=eval("form.Type_"+i+".value");
fieldName=eval("form.fieldName_"+i+".value");
fieldForce=eval("form.Force_"+i+".value");
if (fieldForce=="True"){
if(fieldType=="TEXT") {
if(isEmpty(eval("form." + fieldName),"第 "+i+" 题"))
return false;
}
else
if(! isSelected(eval("form."+fieldName),"第 "+i+" 题"))
return false;
}
}
return true;
}
function isEmpty(field,msg) {
var v=field.value;
v = v.trim();
if(v==null || v=="" ) {
alert("请填好 "+msg+" 的内容");
field.focus();
return true;
}
return false;
}
function isSelected(field, msg) {
var selected=false;
for (var i=0;i<field.length;i++)
if(field[i].checked) {
selected=true;
break;
}
if(!selected)
alert("请填写好 "+msg+" 的内容");
return selected;
}

</script>

Answer 2

<script language="javascript">
function checkReg(){
var user=document.form.username;
var pass=document.form.password;
var pass2=document.form.password2;
if(user.value==""){
alert("用户名不能为空");
user.focus();
return false;
}
if(pass.value==""){
alert("请输入密码");
pass.focus();
return false;
}
if(pass2.value!=pass.value){
alert("两次输入的密码不一致");
pass2.focus();
return false;
}
}
</script>
<div align="center">
<form method="post" name="form" id="form" onSubmit="return checkReg()" action="">
<table width="344" border="0" cellspacing="1" bgcolor="#6666FF">
<tr>
<td height="25" colspan="2">新用户注册</td>
</tr>
<tr>
<td width="110" height="25" align="right" bgcolor="#FFFFFF">用户名:</td>
<td width="218" height="25" bgcolor="#FFFFFF"><input name="username" type="text" id="username" /></td>
</tr>
<tr>
<td height="25" align="right" bgcolor="#FFFFFF">密码:</td>
<td height="25" bgcolor="#FFFFFF"><input name="password" type="password" id="password" /></td>
</tr>
<tr>
<td height="25" align="right" bgcolor="#FFFFFF">确认密码:</td>
<td height="25" bgcolor="#FFFFFF"><input name="password2" type="password" id="password2" /></td>
</tr>
<tr>
<td height="25" colspan="2" align="center" bgcolor="#FFFFFF"><input type="submit" name="Submit" value="注册" />
<input type="reset" name="Submit2" value="重填" />
<input name="menu" type="hidden" id="menu" value="saveReg" /></td>
</tr>
</table>
</form>
</div>