Speeding Up Slow Ajax Requests In WordPress
Identifying Slow Ajax Requests
The first step in speeding up slow Ajax requests in WordPress is to accurately identify which requests are performing poorly. Developers have several analysis techniques at their disposal to pinpoint sluggish queries and narrow down potential optimization targets.
Use Browser Developer Tools to Analyze Network Requests
Modern browsers come equipped with powerful built-in developer tools that allow you to monitor all pending Ajax requests on a given page. By leveraging the “Network” tab in Chrome DevTools, Firefox Developer Tools, or F12 Toolkit in IE/Edge, developers can sorted web requests by speed, filter down to XHR requests, and identify scripts with excessive load times.
Pay special attention to requests that take more than 200ms to return from the server. These assets bottleneck the loading sequence and delay interactivity. Inspect their headers to understand if issues stem from server-side execution or client-side processing constraints.
Check for Unoptimized Images, Scripts, and Stylesheets
Aside from actual XHR queries, a webpage’s associated images, scripts, and stylesheets also impact Ajax speeds. Review these assets for unnecessary bloat that slows down page rendering.
Scan through all images to ensure proper file compression and resizing. Look for oversized or unoptimized files that hurt performance. Similarly, inspect all JS and CSS files for potential minification and concatenation opportunities to reduce overall footprint.
Review Third-Party Plugin Code for Inefficiencies
Many plug-ins enqueue scripts, stylesheets, and other external assets. If not efficiently coded, third-party plugins can significantly slow Ajax requests and DOM rendering.
Test disabling plugins one-by-one to isolate any with direct performance impacts. Then drill into the plugin code to see if you can target any obvious areas for improvement or optimization, either coding changes yourself or requesting they be updated by the plugin author.
Optimizing Images and Media
High-resolution images and expansive media libraries strain servers and substantially impede Ajax calls in WordPress. Luckily, sites can realize huge speed gains through thoughtful optimizations that reduce image footprint.
Resize and Compress Images Before Uploading
Before adding new visual assets, use graphic editing tools like Photoshop or GIMP to manually condense file sizes. With photographs, resize to the appropriate dimensions and compress to find an optimal balance between visual quality and smallest file size.
Similarly, run lossless compression methods like crushing PNGs and converting unsupported formats to incredibly efficient next-gen options like JPEG 2000 and WebP that retain quality while slashing filesize.
Lazy Load Below-the-Fold Images
“Lazy loading” defers offscreen image loading until users scroll to their positions. This prevents rendering resources from being wasted on invisible images. WordPress plugins like BJ Lazy Load automate this process by programmatically loading images only when they become visible.
Serve Images from a CDN Instead of Your Server
Offloading image delivery to a dedicated content delivery network alleviates the burden on your primary application servers to handle static asset requests. This is especially true for resource heavy media like high-resolution photos. Based on visitor geolocation, CDNs also reduce latency by serving images from edge servers closer to end users.
Minifying CSS and JavaScript
Reducing code weight through minification and concatenation are code optimization best practices for accelerating Ajax calls in WordPress. Limiting HTTP requests while slimming asset sizes dramatically cuts load times.
Use a Plugin to Minify and Combine Assets
Instead of manually optimizing scripts and stylesheets, use plugins like WP Rocket or Autoptimize to automate the process. In seconds, these tools can consolidate all CSS and JS files into unified cached assets stored locally on your servers with all extraneous spacing and characters stripped from the code.
Eliminate Unused Code
Carefully comb through CSS and JavaScript files to remove all unused libraries, functions, variables, comments and code blocks. Avoid simply concatenating all site scripts together. Analyze browser developer tools to isolate actually called functions first. Removing unused code directly reduces file sizes.
Load Only Necessary Scripts Per Page
To maximize optimization benefits, ensure that pages only load JavaScript files explicitly needed for page interactivity and components. If specific scripts are only required on some pages, conditionally load them just for those views utilizing wp_enqueue_scripts hooks in your theme.
Caching Ajax Requests
Caching stores server responses so identical future requests avoid redundant database lookups and server-side processing. Implementing comprehensive caching mechanisms is mandatory for achieving fast Ajax performance.
Implement Browser Caching for Unchanged Requests
Configure server headers to set far future expires times and specify cache settings. This allows browsers to store immutable assets like scripts, styles, and images locally. Subsequent page views avoid re-downloading unchanged static files.
WordPress plugins like Cache Enabler help users implement advanced cache headers by file type with ease to minimize server requests.
Use a PHP Caching Plugin to Reduce Database Lookups
WordPress caching plugins build on standard browser caching by generating static HTML copies of backend PHP scripts and queries. This eliminates reliance on resource intensive MySQL queries and PHP execution with each page load.
Effective solutions like WP Fastest Cache offer multilayer caching of HTML, JavaScript, CSS and images for maximum performance.
Cache Full Page Fragments Instead of Small Pieces
Storing complete page sections in cache minimizes DOM erosion from excessive Engineer unnecessary AJAX partial updates that only swap small segments of content. Cache entire visual blocks for fewer rendering interruptions.
For sites with many personalization features requiring constant micro-updates, use JavaScript templating solutions like Mustache.js or marko.js that enable batched reuse of cached DOM portions.
Asynchronous Loading
In contrast to synchronous loading which halts page parsing while assets sequentially download, asynchronous techniques allow HTML document streaming prioritization independent of external scripts. Embracing asynchronicity maximizes loading efficiencies.
Load Non-Critical Assets Asynchronously
Configure external libraries like jQuery to load asynchronously so they do not block rendering. Script loader tools like loadCSS also enable asynchronous CSS loading through onload callbacks.
By carefully orchestrating execution order and resource priorities, sites prevent stalls while loading tertiary assets.
Prioritize Visible Content First
Above-the-fold content with direct user impact should take clear precedence over anything offscreen on initial load.
Prioritize hero images, call-to-action buttons and viewport imagery over ancillary media like decorative graphics.
Consider selectively disabling assets with JS by dynamically swapping placeholder images for actual visuals only after completing initial render.
Use Deferred Loading for Offscreen Images
As covered previously, lazy load plugins only inject images as they enter the viewport. Take this concept a step further by embracing broader deferred loading techniques that programmatically delay offscreen assets until after completing initial document parse.
This prevents hidden images from interfering with critical page contents. Scripts like unveil.js implement this by allowing explicit deferred status and load triggers to be set on DOM elements.
Analyzing Performance Improvements
After implementing optimizations, continuously measure their impact through performance testing. Ensure enhancements deliver expected speed boosts before launching to production.
Retest Page Load Times After Optimizations
Use speed analysis tools including WebPageTest, Chrome User Experience Report, and Lighthouse to benchmark optimization efficacy. Retest key pages to confirm intended improvements by measuring metrics like page load speed, Time To Interactive, and Speed Index.
If speed gains underperform expectations, use profiling tools to isolate remaining laggards and continue honing enhancements targeting them.
Check for Bottlenecks with Web Developer Tools
Browser developer tools reveal lower-level insights not obvious from high-level speed checkers. Inspect sequence of operations during load revealing individual network calls or rendering steps disproportionately slowing things down.
As an example, a single unoptimized image pulling down page interactive times. Alternately, code-split bundles unsuccessfully preventing renderer blocking. Address newly visible bottlenecks.
Continue Refinements Until Goals are Reached
View optimization as an ongoing journey without a single finish line. As new scripts get added, image libraries grow, and pages expand over time, continuously return to analyze if accumulated bloat slows things down.
Revisit speed testing and analytics several times a year to catch growing inertia before it turns into a performance problem. By frequently assessing efficiency, sites sustain speed gains from initial optimizations.
