Kiểm tra Form đăng ký HTML

function formCheck(formobj){

var fieldRequired = Array("FirstName", "LastName","Gioitinh","Age");

var fieldDescription = Array("First Name", "Last Name","Gioitinh","Age");

var alertMsg = "Please complete the following fields: ";

var l_Msg = alertMsg.length;

for (var i = 0; i < fieldRequired.length; i++){
var obj = formobj.elements[fieldRequired[i]];
if (obj){
switch(obj.type){
case "select-one":
if (obj.selectedIndex == -1 || obj.options[obj.selectedIndex].text == ""){
alertMsg += " - " + fieldDescription[i] + " ";
}
break;
case "select-multiple":
if (obj.selectedIndex == -1){
alertMsg += " - " + fieldDescription[i] + " ";
}
break;
case "text":
case "textarea":
if (obj.value == "" || obj.value == null){
alertMsg += " - " + fieldDescription[i] + " ";
}
break;
default:
}
if (obj.type == undefined){
var blnchecked = false;
for (var j = 0; j < obj.length; j++){
if (obj[j].checked){
blnchecked = true;
}
}
if (!blnchecked){
alertMsg += " - " + fieldDescription[i] + " ";
}
}
}
}

if (alertMsg.length == l_Msg){
return true;
}else{
alert(alertMsg);
return false;
}
}
// -->
</script>

<form name="formcheck" onsubmit="return formCheck(this);">
<table border="0" cellpadding="8" cellspacing="0" width="50%">
<tr>
<td align="right" nowrap>First Name:</td>
<td><input type=text name="FirstName" size="25"></td>
</tr>
<tr>
<td align="right" nowrap>Last Name:</td>

<td><input type=text name="LastName" size="25"></td>
</tr>
<tr>
<td align="right" nowrap>Gioitinh:</td>
<td>
Male <input name="Gioitinh" type="radio">
Female <input name="Gioitinh" type="radio">
</td>

</tr>
<tr>
<td align="right" valign="top" nowrap>Age:</td>
<td>
<select name="Age" size="7">
<option>0 - 15
<option>15 - 21
<option>21 - 30
<option>31 - 40
<option>41 - 50
<option>51 - 60
<option>Above 60
</select></td>

</tr>
<tr>
<td class="center" colspan="2">
<input type=submit value="Submit Form">
<input type=reset value="Reset Form">
</td>
</tr>
</table>
</form>

<script>
function KiemTra() { myFrmObj = document.DKUser
if (document.DKUser.textTenDN.value == "")
{
// Hien thi thong bao
window.alert("Ten dang nhap khong duoc de trong.");
document.DKUser.textTenDN.focus();
return false;
}
else if (document.DKUser.textMatkhau.value == "") {
window.alert("Mat khau khong duoc de trong.");
document.DKUser.textMatkhau.focus();
return false;
}
else if (document.DKUser.textMatkhau.value.length < 5) {
window.alert("Mat khau ngan qua.");
document.DKUser.textMatkhau.focus(); return false;
}
else if (document.DKUser.textMatkhau.value !=
document.DKUser.textMatkhaugolai.value) {
window.alert("Mat khau go lai khong dung.");
document.DKUser.textMatkhaugolai.focus();
return false;
}

return true;
}</script>

<form name="DKUser" method="POST" action="Dangkythanhcong.htm" onsubmit="return KiemTra()"><table width="400" border="1" cellpadding="2">
<tr>
<td width="75">ten</td>
<td width="305"><input name="textTenDN" type="text" size="20"></td>
</tr>
<tr>
<td>mk</td>
<td><textarea name="textMatkhau" cols="15"></textarea></td>
</tr>

<tr>
<td>go lai </td>
<td><input name="textMatkhaugolai" type="password" size="15"></td>
</tr>

</table><input type="submit" value="Đăng ký" name="btDangky"><input type="reset" value="Xóa" name="btXoa">
</form>

var emailfilter=/^w+[+.w-]*@([w-]+.)*w+[w-]*.([a-z]{2,4}|d+)$/i

function checkmail(e){
var returnval=emailfilter.test(e.value)
if (returnval==false){
alert("Please enter a valid email address.")
e.select()
}
return returnval
}

</script>

<form>
<input name="myemail" type="text" style="width: 270px"> <input type="submit" onClick="return checkmail(this.form.myemail)" value="Submit" />

</form>