<code>function check_form(){ usernameObj = $("#userName")[0]; //window.alert(usernameObj.value); //show usernameObj=[object HTMLInputElement] var language = $("#choose_language").val(); if(usernameObj.value==''){ showWarningMsg("<?php echo $L['enter_you_user_name']; ?>"); return false; } pwdObj = $("#password")[0]; if(pwdObj.value==''){ showWarningMsg("<?php echo $L['enter_you_user_password']; ?>"); return false; } var yanzheng = $("#user_varify").val(); if(yanzheng==""&&yanzheng.length!=4){ showWarningMsg("<?php echo $L['enter_you_user_yz']; ?>"); return false; } requestUrl = formatAjaxUrl("std-index.php"); $.post(requestUrl, {"language":language,"action":"login_in","username":usernameObj.value, "password": hex_md5(pwdObj.value)+"<?php echo $_SESSION["salt"]; ?>", "choose": document.getElementById("checkednames").value, "remember": "0","yanzheng":yanzheng}, function(data, textStatus) { if (textStatus=="success") { errorCode = getErrorCode(data); switch (errorCode) { case 0: window.location = "<?php echo HOME_URL; ?>"; break; case 1: case 2: showWarningMsg("<?php echo $L['user_password_not_match']; ?>"); break; case 3: showWarningMsg("<?php echo $L['MSG_ERROR_LOCK']; ?>"); break; case 4: userHasLogin("<?php echo $L['MSG_ERROR_RELOGIN']; ?>"); break; case 5: showWarningMsg("<?php echo $L['user_yz_not_match']; ?>"); refresh_img(); break; case 6: showWarningMsg("<?php echo $L['user_yz_outtime_login_agin']; ?>"); refresh_img(); break; case 9: break; case 10: // admin & license doesn't exist window.location = "i2/wizard/wiz_license.php"; break; case 11: // admin & notice something window.location = "i2/wizard/wiz_notice.php"; break; case 12: // non-admin user & license doesn't exist showWarningMsg("<?php echo $L['SW_LICENSE_UNREGISTER']; ?>"); break; case 13: // non-admin & trial license expired showWarningMsg("<?php echo $L['SW_LICENSE_EXPIRED']; ?>"); break; case 20: // upgrade database fail errorMsg = getErrorMsg(data); showWarningMsg("<?php echo $L['MSG_ERROR_DB_CHECK_FAIL']; ?>" + errorMsg); break; case 99: errorMsg = getErrorMsg(data); showWarningMsg( errorMsg ); break; } } }); return false; }</code>
①$("#userName")[0]中的这个【0】表示什么意思呀?
②函数最后加了一个return false;它的作用是什么呢?能否省略?
请大神赐教!
<code>function check_form(){ usernameObj = $("#userName")[0]; //window.alert(usernameObj.value); //show usernameObj=[object HTMLInputElement] var language = $("#choose_language").val(); if(usernameObj.value==''){ showWarningMsg("<?php echo $L['enter_you_user_name']; ?>"); return false; } pwdObj = $("#password")[0]; if(pwdObj.value==''){ showWarningMsg("<?php echo $L['enter_you_user_password']; ?>"); return false; } var yanzheng = $("#user_varify").val(); if(yanzheng==""&&yanzheng.length!=4){ showWarningMsg("<?php echo $L['enter_you_user_yz']; ?>"); return false; } requestUrl = formatAjaxUrl("std-index.php"); $.post(requestUrl, {"language":language,"action":"login_in","username":usernameObj.value, "password": hex_md5(pwdObj.value)+"<?php echo $_SESSION["salt"]; ?>", "choose": document.getElementById("checkednames").value, "remember": "0","yanzheng":yanzheng}, function(data, textStatus) { if (textStatus=="success") { errorCode = getErrorCode(data); switch (errorCode) { case 0: window.location = "<?php echo HOME_URL; ?>"; break; case 1: case 2: showWarningMsg("<?php echo $L['user_password_not_match']; ?>"); break; case 3: showWarningMsg("<?php echo $L['MSG_ERROR_LOCK']; ?>"); break; case 4: userHasLogin("<?php echo $L['MSG_ERROR_RELOGIN']; ?>"); break; case 5: showWarningMsg("<?php echo $L['user_yz_not_match']; ?>"); refresh_img(); break; case 6: showWarningMsg("<?php echo $L['user_yz_outtime_login_agin']; ?>"); refresh_img(); break; case 9: break; case 10: // admin & license doesn't exist window.location = "i2/wizard/wiz_license.php"; break; case 11: // admin & notice something window.location = "i2/wizard/wiz_notice.php"; break; case 12: // non-admin user & license doesn't exist showWarningMsg("<?php echo $L['SW_LICENSE_UNREGISTER']; ?>"); break; case 13: // non-admin & trial license expired showWarningMsg("<?php echo $L['SW_LICENSE_EXPIRED']; ?>"); break; case 20: // upgrade database fail errorMsg = getErrorMsg(data); showWarningMsg("<?php echo $L['MSG_ERROR_DB_CHECK_FAIL']; ?>" + errorMsg); break; case 99: errorMsg = getErrorMsg(data); showWarningMsg( errorMsg ); break; } } }); return false; }</code>
①$("#userName")[0]中的这个【0】表示什么意思呀?
②函数最后加了一个return false;它的作用是什么呢?能否省略?
请大神赐教!
我能很喜感的说,菜鸟看菜鸟写的代码吗?
两句都是废话。
$('#userName')表示根据id查找对象,但是html规范中id是唯一的,所以这里的[0]虽然是得到了js原生对象,但是实际上一点用都没有,参考后面的
var yanzheng = $("#user_varify").val();
同样的
<code>usernameObj = $("#userName")[0]; if(usernameObj.value==''){ showWarningMsg("<?php echo $L['enter_you_user_name']; ?>"); return false; }</code>
可以等效为
<code>usernameObj = $("#userName")[0]; if(! $("#userName").val().length){ showWarningMsg("<?php echo $L['enter_you_user_name']; ?>"); return false; }</code>
结尾的return false用来阻止事件冒泡,但是源码中的onclick="check_form(); return false;"既然又写了一个return false,那么函数里面那个写不写都没用,反正没挂return。
正确的方式是