diff --git a/web/src/reader/reader.ts b/web/src/reader/reader.ts
index 0ff9d53..ad9882d 100644
--- a/web/src/reader/reader.ts
+++ b/web/src/reader/reader.ts
@@ -384,6 +384,7 @@ document.addEventListener("alpine:init", () => {
     mediaItemId: "" as string,
     saveTimeout: null as ReturnType<typeof setTimeout> | null,
     initTime: 0 as number,
+    contextText: "" as string,
     readingTheme: "light" as string,
     readingMode: "light" as string,
     readingFont: "literata" as string,
@@ -504,6 +505,11 @@ document.addEventListener("alpine:init", () => {
           slider.value = fraction;
           slider.title = progressStr;
         }
+        const range = e.detail.range as Range | undefined;
+        if (range) {
+          const text = range.toString().replace(/\s+/g, " ").trim();
+          this.contextText = text ? text.slice(0, 100) : "";
+        }
         this.debouncedSaveProgress(fraction, location, cfi);
       });
       const slider = document.getElementById(
@@ -566,6 +572,7 @@ document.addEventListener("alpine:init", () => {
       };
       if (!this.isFixedLayout) {
         body.epubcfi = cfi || "";
+        body.context_text = this.contextText || "";
       }
 
       const tocItem = this.lastRelocateDetail?.tocItem;