diff --git a/app/src/main/java/io/legado/app/utils/StringExtensions.kt b/app/src/main/java/io/legado/app/utils/StringExtensions.kt
index 957d5b091..23f35a357 100644
--- a/app/src/main/java/io/legado/app/utils/StringExtensions.kt
+++ b/app/src/main/java/io/legado/app/utils/StringExtensions.kt
@@ -1,3 +1,6 @@
 package io.legado.app.utils
 
-fun String?.strim() = if (this.isNullOrBlank()) null else this.trim()
\ No newline at end of file
+fun String?.strim() = if (this.isNullOrBlank()) null else this.trim()
+
+fun String.isAbsUrl() = this.startsWith("http://", true)
+        || this.startsWith("https://", true)