javascript - 简单的表单验证

Question

发布#1

如何验证这个简单的表单(检查空字段字符串)？

                <p>Please select your Gift Certificate amount below. Please also enter your name and the Gift Certificate recipient's name. Once you click 'Buy Now' you will be sent to our Paypal site to complete the purchase.</p>

                    <form action="https://www.paypal.com/cgi-bin/webscr" method="post">
        <input type="hidden" name="cmd" value="_s-xclick">
        <input type="hidden" name="hosted_button_id" value="sdsafsdafsadfdsafsdafsadfsadfsadfasdfsadfsdaf">
        <table width="100%">
        <tr>
            <td width="130"><input type="hidden" name="on0" value="Amount"><p>Amount</p></td>
            <td><select name="os0">
            <option value="Option 1">$20.00</option>
            <option value="Option 2">$50.00</option>
            <option value="Option 3">$100.00</option>
            </select></td>
        </tr>
        <tr>
            <td><input type="hidden" name="on1" value="To:"><p>To (Full Name):</p></td>
            <td><input type="text" name="os1" maxlength="60" size="30"></td>
        </tr>
        <tr>
            <td><input type="hidden" name="on2" value="From:"><p>From (Full Name):</p></td>
            <td><input type="text" name="os2" maxlength="60" size="30"></td>
        </tr>
        </table>

        <table width="100%" style="margin-top: 10px;">
            <tr>
                <td><input type="hidden" name="currency_code" value="CAD">
        <p><input type="image" src="BUTTON.jpg" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!"></p>
        <img alt="" border="0" src="https://www.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1"></td>
                <td align="right"><img src="../paypal_logo.jpg" alt="PayPal" /></td>
            </tr>
        </table>
        </form>

发布#2

函数 validate_form(){ 有效=真；

    if ( document.GiftForm.os1.value == "" )
    {
        alert ( "Please fill in the 'Your Name' box." );
        valid = false;
    }
    return valid;
}

-=-=-=-= 表格

        <form action="https://www.paypal.com/cgi-bin/webscr" method="post" method="GiftForm" onsubmit="validate_form( )">
        <input type="hidden" name="cmd" value="_s-xclick">
        <input type="hidden" name="hosted_button_id" value="sdsafsdafsadfdsafsdafsadfsadfsadfasdfsadfsdaf">
        <table width="100%">
        <tr>
            <td width="130"><input type="hidden" name="on0" value="Amount"><p>Amount</p></td>
            <td><select name="os0">
            <option value="Option 1">$20.00</option>
            <option value="Option 2">$50.00</option>
            <option value="Option 3">$100.00</option>
            </select></td>
        </tr>
        <tr>
            <td><input type="hidden" name="on1" value="To:"><p>To (Full Name):</p></td>
            <td><input type="text" name="os1" maxlength="60" size="30"></td>
        </tr>
        <tr>
            <td><input type="hidden" name="on2" value="From:"><p>From (Full Name):</p></td>
            <td><input type="text" name="os2" maxlength="60" size="30"></td>
        </tr>
        </table>

        <table width="100%" style="margin-top: 10px;">
            <tr>
                <td><input type="hidden" name="currency_code" value="CAD">
        <p><input type="image" src="BUTTON.jpg" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!"></p>
        <img alt="" border="0" src="https://www.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1"></td>
                <td align="right"><img src="../paypal_logo.jpg" alt="PayPal" /></td>
            </tr>
        </table>
        </form>

Answer 1

jQuery 是一个选项吗？有一个非常好的验证工具 http://docs.jquery.com/Plugins/Validation