ผมทำการตรวจสอบการใส่ข้อมูล แต่มันทำไม่ได้ ดูให้หน่อยว่าผิดบรรทัดใหนครับ

<script type="text/javascript">
function IsCheck(txtName, txtAddress, txtPhone, txtFax, txtEmail, txtWeb, txtConnect, txtPosition, txtCredit)
	{
		//alert(eText);
		if(document.getElementById(txtName).value == '' 
		&& document.getElementById(txtAddress).value == ''
		&& document.getElementById(txtPhone).value == '' 
		&& document.getElementById(txtFax).value == ''
		&& document.getElementById(txtEmail).value == ''
		&& document.getElementById(txtWeb).value == ''
		&& document.getElementById(txtConnect).value == '' 
		&& document.getElementById(txtPosition).value == ''
		&& document.getElementById(txtCredit).value == ''
		
		)
		{
			alert('กรุณาใส่ข้อมูล');
			return false;
		}
		else if(document.getElementById(txtName).value == '' 
		|| document.getElementById(txtAddress).value == '' 
		|| document.getElementById(txtPhone).value == '' 
		|| document.getElementById(txtFax).value == ''
		|| document.getElementById(txtEmail).value == ''
		|| document.getElementById(txtWeb).value == '' 
		|| document.getElementById(txtConnect).value == '' 
		|| document.getElementById(txtPosition).value == ''
		|| document.getElementById(txtCredit).value == ''
		
		)
		{
			alert('กรุณาใส่ข้อมูลให้ครบ');
			return false;
		}
		var txtPhoneFilter=/^([0-9]){1,}$/;
		var txtPhone=document.form1.txtPhone.value;
		
		if (!(txtPhoneFilter.test(txtPhone))) 
		{ 
       		alert ("เบอร์โทรศัพท์ต้องป็นตัวเลข");
	   		return false;
		}
		var txtFaxFilter=/^([0-9]){1,}$/;
		var txtFax=document.form1.txtFax.value;
		
		if (!(txtFaxFilter.test(txtFax))) 
		{ 
       		alert ("เบอร์โทรสารต้องป็นตัวเลข");
	   		return false;
		}
		var txtCreditFilter=/^([0-9]){1,}$/;
		var txtCredit=document.form1.txtCredit.value;
		
		if (!(txtCreditFilter.test(txtCredit))) 
		{ 
       		alert ("ปล่อยเครดิตต้องป็นตัวเลข");
	   		return false;
		}
		var txtEmailFilter=/^.+@.+\..{2,3}$/;
		var txtEmail=document.form1.txtEmail.value;
		
		if (!(txtEmailFilter.test(txtEmail))) 
		{ 
       		alert ("อีเมล์ไม่ถูกต้อง");
	   		return false;
		}
		else
		return true;
	}
</script>

<label>
                        <input input type="submit" name="btnSubmit" onclick= "return IsCheck('txtName','txtAddress','txtPhone','txtFax','txtEmail','txtWeb','txtConnect','txtPosition','txtCredit');" value="ตกลง" style="width:100px" />
                      </label>