implement buttons

static/buttons.js

@@ -0,0 +1,46 @@
+function forward(){
+
+    var url   = new URL(window.location.href)
+    var start = url.searchParams.get("start")
+    var page  = url.searchParams.get("page")
+    
+    if(page){
+        page = parseInt(page) + 1
+    }else if(start){
+        page = Math.trunc(parseInt(start)/100) + 1
+    }else{
+        page = 1
+    }
+    
+    url.searchParams.set("page", page)
+    window.location.href = url.href
+
+}
+function backward(){
+
+    var url   = new URL(window.location.href)
+    var start = url.searchParams.get("start")
+    var page  = url.searchParams.get("page")
+    
+    if(page){
+        page = parseInt(page) - 1
+        if(page < 0){
+            page = 0
+        }
+    }else if(start){
+        page = Math.trunc(parseInt(start)/100) - 1
+    }else{
+        page = 0
+    }
+    
+    url.searchParams.set("page", page)
+    window.location.href = url.href
+}
+
+function firstPage(){
+    var href = window.location.href
+    var parameterSeperator = "?"
+    if(href.includes(parameterSeperator)){
+        window.location.href = href.split(parameterSeperator)[0]
+    }
+}