Question

我想选择第一个免费课程的td（td class =＆＃34; free＆＃34; ..）。如何在页面加载时选择第一个td。如何实现这个jquery或javascript？请帮忙......

由于很多人不清楚，我会简要解释一下。我有一个选项让客户选择他们交付的可用时间，基本上我想为他们选择第一次，所以我想为他们保存一次点击，但他们可以改变它，如果他们想。可用时间的课程是免费的，这就是我问上面的问题。

Answer 1

这很简单

$('td.free').first();

示例：

console.log($('td.free').first().text());

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<table>
  <tr>
    <td>1</td>
    <td>2</td>
  </tr>
  <tr>
    <td class="free">3</td>
    <td class="free">4</td>
  </tr>
</table>

Answer 2

你走了：

<Style x:Key="MyPasswordBoxStyle" TargetType="PasswordBox">
        <Setter Property="MinWidth" Value="{ThemeResource TextControlThemeMinWidth}"/>
        <Setter Property="MinHeight" Value="{ThemeResource TextControlThemeMinHeight}"/>
        <Setter Property="SelectionHighlightColor" Value="{ThemeResource TextSelectionHighlightColorThemeBrush}"/>
        <Setter Property="Foreground" Value="White"/>
        <Setter Property="Background" Value="{ThemeResource TextBoxBackgroundThemeBrush}"/>
        <Setter Property="BorderBrush" Value="{ThemeResource TextBoxBorderThemeBrush}"/>
        <Setter Property="BorderThickness" Value="{ThemeResource TextControlBorderThemeThickness}"/>
        <Setter Property="FontFamily" Value="{ThemeResource PhoneFontFamilyNormal}"/>
        <Setter Property="FontSize" Value="{ThemeResource ContentControlFontSize}"/>
        <Setter Property="ScrollViewer.HorizontalScrollMode" Value="Auto"/>
        <Setter Property="ScrollViewer.VerticalScrollMode" Value="Auto"/>
        <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Hidden"/>
        <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Hidden"/>
        <Setter Property="Padding" Value="{ThemeResource TextControlThemePadding}"/>
        <Setter Property="Margin" Value="{ThemeResource TextControlMarginThemeThickness}"/>
        <Setter Property="VerticalAlignment" Value="Top"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="PasswordBox">
                    <Grid Background="Transparent">
                        <Grid.RowDefinitions>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition Height="*"/>
                            <RowDefinition Height="Auto"/>
                        </Grid.RowDefinitions>
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledBackgroundThemeBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledBorderThemeBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledForegroundThemeBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="PlaceholderTextContentPresenter">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledForegroundThemeBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="HeaderContentPresenter">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledHeaderForegroundThemeBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Normal">
                                    <Storyboard>
                                        <DoubleAnimation Duration="0" To="{ThemeResource TextControlBorderThemeOpacity}" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BorderElement"/>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="PointerOver"/>
                                <VisualState x:Name="Focused">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextSelectionHighlightColorThemeBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <DoubleAnimation Duration="0" To="0" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="PlaceholderTextContentPresenter"/>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ClubCardBlueColorBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                            <VisualStateGroup x:Name="ButtonStates">
                                <VisualState x:Name="ButtonVisible">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="RevealButton">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="IsChecked" Storyboard.TargetName="RevealButton">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="False"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="ButtonCollapsed">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="RevealButton">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="IsChecked" Storyboard.TargetName="RevealButton">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="False"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Border x:Name="BorderElement" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.Row="1"/>
                        <ContentPresenter x:Name="HeaderContentPresenter" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" Margin="{ThemeResource TextControlHeaderMarginThemeThickness}" Grid.Row="0" Style="{StaticResource HeaderContentPresenterStyle}"/>
                        <ScrollViewer x:Name="ContentElement" AutomationProperties.AccessibilityView="Raw" HorizontalScrollMode="{TemplateBinding ScrollViewer.HorizontalScrollMode}" HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}" IsTabStop="False" IsHorizontalRailEnabled="{TemplateBinding ScrollViewer.IsHorizontalRailEnabled}" IsVerticalRailEnabled="{TemplateBinding ScrollViewer.IsVerticalRailEnabled}" Margin="{ThemeResource RichEditBoxTextThemeMargin}" MinHeight="{ThemeResource TextControlThemeMinHeight}" Padding="{TemplateBinding Padding}" Grid.Row="1" VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}" VerticalScrollMode="{TemplateBinding ScrollViewer.VerticalScrollMode}" ZoomMode="Disabled"/>
                        <ContentControl x:Name="PlaceholderTextContentPresenter" Content="{TemplateBinding PlaceholderText}" Foreground="{ThemeResource TextBoxPlaceholderTextThemeBrush}" IsTabStop="False" Margin="{ThemeResource RichEditBoxTextThemeMargin}" Padding="{TemplateBinding Padding}" Grid.Row="1"/>
                        <CheckBox x:Name="RevealButton" Foreground="{ThemeResource TextBoxForegroundHeaderThemeBrush}" HorizontalAlignment="Left" IsTabStop="False" Margin="{ThemeResource PasswordBoxCheckBoxThemeMargin}" Grid.Row="2" Visibility="Collapsed" VerticalAlignment="Top"/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

使用jquery或javascript选择第一个td类

2 个答案: