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Article Introduction：Selecting Options for a Drop-Down Box from MySQL in PHPFilling a drop-down box with data from a MySQL query can be a challenge for those new to...

2024-11-13 comment 0  472

Article Introduction：The Create H5 drop-down menu includes the following steps: Create a drop-down list, apply a CSS style, add toggle effects, and handle user selections. The specific steps are as follows: Use HTML to create a drop-down list. Use CSS to adjust the appearance of the drop-down menu. Use JavaScript or CSS to achieve the switching effect. Listen to change events to handle user selections.

2025-04-06 comment 0  1271

Article Introduction：Styling the Hover Effect of OptionsThe element provides a drop-down list for user input selection. When the cursor...

2024-11-01 comment 0  1099

Article Introduction：BootstrapNavbar provides a variety of advanced usage and tricks to optimize the user experience. 1. Dynamically adjust the style of Navbar: Use JavaScript to change the background color or transparency. 2. Add search box: Integrate search functions to improve the convenience of finding content. 3. Use the drop-down menu: Show more options in a limited space. 4. Responsive design: Adjust the display effect on different devices through CSS media query. These methods can improve the user experience, but pay attention to performance and maintenance.

2025-07-04 comment 0  970

Article Introduction：To ensure that the user must select an option from the drop-down menu in the HTML form, use the required property to implement required verification. 1. Add required attribute to the tag, 2. Set the first value to an empty string to trigger verification failure, 3. You can simulate the placeholder effect through disabled and selected, 4. If you need more flexible control, you can manually judge the selected value by JavaScript. Correctly setting the null value option is the key to ensuring validation takes effect.

2025-07-11 comment 0  126

Article Introduction：MySQL indexes are not as fast as possible, and they need to be used reasonably according to the query scenario. 1. The WHERE condition medium value query (=) has the best effect. The range query must comply with the principle of leftmost prefix. Fuzzy match LIKE'abc%' can be indexed, LIKE'?c' is not available, and functions or expressions are avoided in the condition. 2. ORDERBY needs to use indexes to avoid file sorting. It requires that the sorting columns have indexes and the WHERE and ORDERBY columns are in the same order to form a joint index, but range query may cause the sorting to be invalid. 3. GROUPBY recommends using an existing index structure, which prioritizes indexes covering equivalent conditions. Discontinuous columns or inappropriate order will add additional overhead. In addition, the EXPLAIN tool should be paid attention to the implementation plan

2025-07-24 comment 0  654

Article Introduction：The key to creating a dependency drop-down list in Excel is to understand the use of data structures and functions. There are three main methods. 1. First organize the basic data source, such as the classification and corresponding subitems are listed separately, and it is recommended to use naming scope management; 2. Use the "Data Verification" "INDIRECT" function to achieve linkage, provided that the main pull-down option is consistent with the named area name; 3. Use the FILTER function (suitable for Excel365 or 2021 and above), and achieve more flexible linkage through dynamic filtering. The formula is =UNIQUE (FILTER (sub-item column, classification column =main pull-down cell)). Pay attention to naming specifications, tidy data and function limitations to ensure smooth secondary linkage effect.

2025-07-22 comment 0  1000

Article Introduction：How to set text color gradient in PS: Create text layer: Enter text using the Text Tool (T). Open the Gradient Editor: Select Gradient from the Window menu. Select Gradient Type: Select Linear, Radial, or Angle types from the drop-down menu. Set gradient color: Click gradient to stop selecting color. Adjust Gradient Position: Use sliders or numeric fields to adjust the position. Apply Gradients: Click the OK button to apply changes. Save changes: Save the file to apply a gradient effect.

2025-04-06 comment 0  322

Article Introduction：MySQL index may not be used in the following situations: 1. The query conditions do not match the index column or do not start from the leftmost column of the joint index; 2. Perform function or expression operations on the index field; 3. Fuzzy queries starting with % of LIKE; 4. The query conditions do not match the index column data type; 5. The index selectivity is too low, causing the optimizer to give up on use. For example, if the joint index (name,age) is only queried, it will not take effect; using YEAR(create_time)=2023 will cause the index to be invalid; LIKE'?c' cannot go through the index and scan the full table; VARCHAR fields use numerical query to trigger implicit conversion; low-selective fields such as gender fields may be ignored by the optimizer. Mastering these situations helps

2025-06-19 comment 0  572

Article Introduction：The key to creating a drop-down menu is the use of HTML structure and CSS. First, build a structure with an unordered list, the main menu item is the top level, and the submenu is nested inside it, for example, using nested ones. Secondly, control the hiding and display of the submenu through CSS, set .submenu{display:none;position:absolute;}, and display it when hovering: .dropdown:hover.submenu{display:block;}. Finally, you can add style details such as background color, hover effect, border shadow, etc. to improve the beauty and user experience.

2025-07-18 comment 0  664

Article Introduction：:hover pseudo-class is used to apply styles when hovering. 1. The basic syntax is selector:hover{style}, such as a:hover{color:red}; 2. Common uses include button color change, picture zooming and drop-down menu display; 3. Notes include inconsistent behavior of the mobile terminal, accessibility and performance optimization need to be considered; 4. In advanced examples, shadows, displacements and border changes are added when card hovering, and smooth animation is achieved with transition. The final effect is to improve the interactive experience but the full platform needs to be tested to ensure usability.

2025-07-25 comment 0  220

Article Introduction：There are three ways to adjust the resolution of Windows 11 screen: 1. Adjust through the "Settings" menu, open the "Start Menu" and select "Settings", enter the "System"-"Display" and find the "Show Resolution" drop-down menu, and select the recommended options; 2. Right-click the desktop to quickly adjust, click "Show Settings" and then operate the same as above; 3. Troubleshoot the reasons when encountering problems, such as updating the graphics card driver, checking the connection cable, confirming the monitor support range, etc. Each approach corresponds to different scenarios, ensuring resolution is adapted to the display for the best visual effect.

2025-07-09 comment 0  379

Article Introduction：There is no startup sound when Windows 11 is powered on by default, but if you enable the relevant settings or use an earlier version of the system upgraded, you may hear the startup sound effect. If you want to turn off or change this sound, the operation is not complicated. Find the "System Sound" setting First, you need to enter the sound settings section of the system. Right-click the volume icon in the lower right corner of the taskbar and select "Sound Settings". Then in the window that opens, scroll down and click "Sound Settings Advanced Controls", and then you will see a link to "Sound Control Panel" and click it. Here you will see a drop-down menu called "Sound Scheme", which lists the sounds corresponding to various system events. Find the "Windows boot" item, its silent

2025-06-28 comment 0  844

Article Introduction：To rotate a specific page in a PDF, you can use Adobe Acrobat's "Organize Page" tool: 1. Open the PDF and go to "Tools" > "Organize Pages", and click the rotation button to adjust the direction in the thumbnail panel on the right. 2. For regular multi-page rotation, you can set the angle and specific page number range in the "Rotate" drop-down menu, and click "Apply"; 3. After rotation, be sure to check the page display and printing effect. If necessary, you can repeatedly adjust or view the rotation settings of the original scanned file. It is recommended to save the copy before operation to prevent accidents.

2025-07-12 comment 0  165

Article Introduction：There are three ways to adjust the Windows screen resolution 1. Right-click the desktop and select "Display Settings" and select the appropriate value in the "Display Resolution" drop-down menu and save it; 2. Find "Adjust Screen Resolution" through the small icon mode of the control panel to set it; 3. If you encounter problems, you can wait for the system to automatically restore, restart the Explorer or enter safe mode to adjust, and ensure that the graphics card driver is the latest version. Each method can achieve resolution adjustment, but it needs to be reasonably selected according to the monitor support range to ensure the display effect.

2025-07-23 comment 0  143

Article Introduction：CSS transitions enable switching between CSS attribute values ??through smooth animations, which are suitable for user interaction scenarios such as button hovering effects, menu expansion and collapse. Common usages include button closure effect, drop-down menu gradient, background color gradient, image transparency or zoom changes. The basic syntax is a transition: attribute duration time sequence function, which can specify a single or multiple attributes, or all can be used to represent all attributes, but it should be used with caution. Timing functions such as ease, linear, and ease-in-out control the animation speed curve, and can also be customized by cubic-bezier. It is recommended to prioritize opacity and transform for better performance, combined with @media(prefers-

2025-07-01 comment 0  314

Article Introduction：Just a few days ago, one of our users reported an unusual problem. The problem is that he reaches the limit of custom menu items. Any content he saves after reaching the menu item limit will not be saved at all. We've never heard of this issue, so we decided to give it a try on our local installation. More than 200 menu items were created and saved. The effect is very good. Move 100 items to the drop-down list and save them very well. Then we knew it had to do with the server. After further research, it seems that many others have encountered the same problem. After digging deeper, we found a trac ticket (?#14134?) that highlighted this issue. Read very

2025-04-18 comment 0  432

Article Introduction：The most direct way to make the input box in the HTML form required is to use the required property. This property is a Boolean type, and no value is required. It can be used to verify it on the input, select or textarea tags, such as:; Common matching types include text, email, password, etc.; for checkbox, directly add required to force check; in the radio button group, just add required to the first option; the select drop-down box needs to set the default empty value option to trigger verification; different browsers may have different styles and contents of prompt information. If a unified prompt effect is required, you can customize it with JavaScript or third-party libraries for customization.

2025-07-07 comment 0  782

Article Introduction：There are many ways to enlarge the picture in PremierePro. 1. Use the "Scaling Tool" (shortcut key Z) to enlarge the view of the timeline; 2. Press and hold the Alt (Windows) or Option (Mac) keys and scroll the mouse wheel, or adjust the preview screen scale through the zoom drop-down menu in the lower right corner of the "Program Monitor"; 3. Modify the "Scaling" value in the "Motion" option of the "Effect Control" panel to add keyframes to create animation effects; 4. nest the sequence and apply a unified zoom value to the entire sequence, which is suitable for overall zooming of multiple layers or complex synthesis. Each method is suitable for different scenarios, and reasonable choice can improve editing efficiency.

2025-07-10 comment 0  170

Article Introduction：Is an element in HTML that provides predefined suggestions for fields, which is used in conjunction with list attributes with matching ids to display drop-down options when user input. The specific steps are as follows: 1. Define and set the id; 2. Use the list attribute to associate the id. For example, the input box will automatically filter and display the matching fruit name based on the user input. Notes include: Users can select suggestions or enter them by themselves, browser support is inconsistent, and JavaScript dynamic fill options are available. In addition, the default filtering method of the browser is simple, and it needs to be implemented manually if advanced filtering (such as fuzzy search). This function is suitable for scenarios that require speeding up data input but allow custom input, such as search bars, city names, labels, etc., but is not suitable for strict

2025-06-30 comment 0  735