Copy the code code as follows:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html"; charset="utf-8">
<title>SMS system</title>
<script language="javascript">
function formcheck(){
if(document.form.zhanghao.value==""){
alert("The number cannot be empty!");
this.form1.zhanghao.focus();
return false;
}else if(document.form.email.value==""){
alert("Content cannot be empty!")
this.form1.eamil.focus();
return false;
}else form1.submit();
}
</script>
</head>
<body>
<form name="form" method="post" action="sendmail.php">
<table>
<h2>
<tr>
<th colspan="8">Send SMS</th>
</tr>
</h2>
<body>
<tr bgcolor="#eeeeee">
<td align="center">Number:</td>
<td><textarea name="content" cols="80" rows="15" id="zhanghao"></textarea></td>
</tr>
<tr bgcolor="#eeeeee">
<td align="center">Content:</td>
<td><textarea name="content" cols="80" rows="15" id="email"></textarea></td>
</tr>
<tr bgcolor="#eeeeee" align="center">
<td colspan="2">
<input type="button" name="Submit" value="Send" onClick="javascript:formcheck();">
<input type="reset" name="Submit2" value="Reset">
</td>
</tr>
</body>
</table>
</form>
</body>
</html>