请问一个原理有关问题

function submit_login(e)<br />{<br />    if (typeof e != 'undefined' && !enter_key_trap(e)) {<br />        return;<br />    }<br /><br />    if (document.horde_login.horde_user.value == "") {<br />        alert("<?php echo addslashes(_("Please provide your username and password")) ?>");<br />        document.horde_login.horde_user.focus();<br />        return false;<br />    } else if (document.horde_login.horde_pass.value == "") {<br />        alert("<?php echo addslashes(_("Please provide your username and password")) ?>");<br />        document.horde_login.horde_pass.focus();<br />        return false;<br />    } else {<br />        document.horde_login.loginButton.disabled = true;<br /><?php if (!empty($ie_clientcaps)): ?><br />        try {<br />            document.horde_login.ie_version.value = objCCaps.getComponentVersion("{89820200-ECBD-11CF-8B85-00AA005B4383}", "componentid");<br />        } catch (e) {<br />        }<br /><?php endif; ?><br />        document.horde_login.submit();<br />        return true;<br />    }<br />}