嗨,我想在提交表单之前验证字段值这是我的代码
<table width="600" border="0" align="left">
<tr>
<script type="text/javascript">
function previewPrint()
{
var RegNumber = document.getElementById('PP_RegNoTextBox').value;
var PassportNo = document.getElementById('PP_PassportNoTextBox').value;
if (RegNumber=="")
{
alert("Please enter your Reg No.!");
document.getElementById('RegNoTextBox').focus();
return false;
}
if (PassportNo=="")
{
alert("Please enter your Passport No.!");
document.getElementById('PassportNoTextBox').focus();
return false;
}
//window.open('regformview.php?RegNumber=RegNumber');
}
</script>
<form name="ppform" onSubmit="return previewPrint();" method="post" action="regformview.php">
<td width="100" align="LEFT" class="font8"> </td>
<td width="337" align="LEFT" class="font8"><u>Preview your Application:</u> Please provide requested details.<br>
Reg No.: <input type="text" name="printregno" id="PP_RegNoTextBox" class="input2"> Passport No.: <input type="text" name="printemail" class="input2"><input type="hidden" name="flagging" id="PP_PassportNoTextBox" value="1" class="input2"> </td>
<td width="50" align="LEFT" class="font8"><div style="float:left; background-image:url(images/printPreview1.jpg); background-repeat:no-repeat;">
<input type="image" src="images/printPreview1.jpg" name="ppbutton" value="" onMouseOver="this.src='images/printPreview2.jpg'" onMouseOut="this.src='images/printPreview1.jpg'"></div></td>
</form>
</tr>
</table>
问题是它是否正确显示警报框,如果它为空白但页面在提交后导航到 regformview.php。如何仅在验证后导航到 regformview.php。?