diff --git a/resources/views/welcome.blade.php b/resources/views/welcome.blade.php
index 7707e99..7530054 100644
--- a/resources/views/welcome.blade.php
+++ b/resources/views/welcome.blade.php
@@ -395,7 +395,7 @@ function fetchMail() {
                             $('#exampleModalLabel').text(text);
                             // 显示模态框
                             $('#myModal').modal('show');
-                            var iframeHeight = $('#modalIframe').contents().find("html").height();
+                            let iframeHeight = $('#modalIframe').contents().find("html").height();
                             console.log("Iframe的实际高度是: " + iframeHeight + "px");
                             if (iframeHeight >= 600){
                                 $('#modalIframe').css('height',600);