diff --git a/app/add.py b/app/add.py
index ba78cbf4..81745bd2 100644
--- a/app/add.py
+++ b/app/add.py
@@ -115,6 +115,10 @@ if form.getvalue('mode') is not None:
 			rewrite = form.getvalue('rewrite')
 		else:
 			rewrite = ""
+		if form.getvalue('prefix'):
+			prefix = form.getvalue('prefix')
+		else:
+			prefix = ""
 		if form.getvalue('nocache'):
 			nocache = form.getvalue('nocache')
 		else:
@@ -127,7 +131,7 @@ if form.getvalue('mode') is not None:
 			dynamic = form.getvalue('dynamic')
 		else:
 			dynamic = ""
-		cookie += " "+rewrite+" "+nocache+" "+postonly+" "+dynamic+"\n"
+		cookie += " "+rewrite+" "+prefix+" "+nocache+" "+postonly+" "+dynamic+"\n"
 		options_split += cookie
 		if form.getvalue('dynamic'):
 			options_split += "    dynamic-cookie-key " + form.getvalue('dynamic-cookie-key')+"\n"
diff --git a/app/templates/add.html b/app/templates/add.html
index 0e99c6ef..43a4fa6a 100644
--- a/app/templates/add.html
+++ b/app/templates/add.html
@@ -86,14 +86,15 @@
 				<span id="cookie_div" style="display: none;">
 					<input type="text" placeholder="name" name="cookie_name" id="cookie_name" class="form-control"><br><br>
 					<input type="text" placeholder="domain" name="cookie_domain" class="form-control"><br><br>
-					<select name="rewrite">
-						<option disabled selected>rewrite/insert/prefix/indirect</option>
+					<select name="rewrite" id="rewrite" class="force_close">
+						<option disabled selected>rewrite/indirect/insert</option>
 						<option>None</option>
 						<option value="rewrite">rewrite</option>
-						<option value="insert">insert</option>
-						<option value="prefix">prefix</option>
 						<option value="indirect">indirect</option>
+						<option value="insert">insert</option>
 					</select>
+					<label for="prefix" style="margin-top: 5px;" title="This keyword indicates that instead of relying on a dedicated cookie for the persistence, an existing one will be completed.">prefix</label>
+					<input type="checkbox" name="prefix" value="prefix" id="prefix">
 					<label for="nocache" style="margin-top: 5px;" title="This option is recommended in conjunction with the insert mode when there is a cache between the client and HAProxy.">nocache</label>
 					<input type="checkbox" name="nocache" value="nocache" id="nocache">
 					<label for="postonly" style="margin-top: 5px;" title="This option ensures that cookie insertion will only be performed on responses to POST requests.">postonly</label>
@@ -322,14 +323,15 @@
 				<span id="cookie_div2" style="display: none;">
 					<input type="text" placeholder="name" name="cookie_name" id="cookie_name2" class="form-control"><br><br>
 					<input type="text" placeholder="domain" name="cookie_domain" class="form-control"><br><br>
-					<select name="rewrite">
-						<option disabled selected>rewrite/insert/prefix/indirect</option>
+					<select name="rewrite" id="rewrite2" class="force_close">
+						<option disabled selected>rewrite/indirect/insert</option>
 						<option>None</option>
 						<option value="rewrite">rewrite</option>
-						<option value="insert">insert</option>
-						<option value="prefix">prefix</option>
 						<option value="indirect">indirect</option>
+						<option value="insert">insert</option>
 					</select>
+					<label for="prefix2" style="margin-top: 5px;" title="This keyword indicates that instead of relying on a dedicated cookie for the persistence, an existing one will be completed.">prefix</label>
+					<input type="checkbox" name="prefix" value="prefix" id="prefix2">
 					<label for="nocache2" style="margin-top: 5px;" title="This option is recommended in conjunction with the insert mode when there is a cache between the client and HAProxy.">nocache</label>
 					<input type="checkbox" name="nocache" value="nocache" id="nocache2">
 					<label for="postonly2" style="margin-top: 5px;" title="This option ensures that cookie insertion will only be performed on responses to POST requests..">postonly</label>
diff --git a/inc/script.js b/inc/script.js
index 43597fad..ac8eb9fc 100644
--- a/inc/script.js
+++ b/inc/script.js
@@ -480,6 +480,20 @@ $( function() {
 			$("#dynamic-cookie-key2" ).attr('required',false);
 		}
 	});
+	$( "#rewrite" ).on('selectmenuchange',function()  {
+		if ($( "#rewrite option:selected" ).val() == "insert" || $( "#rewrite option:selected" ).val() == "rewrite") {
+			$( "#prefix" ).checkboxradio( "disable" );
+		} else {
+			$( "#prefix" ).checkboxradio( "enable" );
+		}
+	});
+	$( "#rewrite2" ).on('selectmenuchange',function()  {
+		if ($( "#rewrite2 option:selected" ).val() == "insert" || $( "#rewrite2 option:selected" ).val() == "rewrite") {
+			$( "#prefix2" ).checkboxradio( "disable" );
+		} else {
+			$( "#prefix2" ).checkboxradio( "enable" );
+		}
+	});
 	$( "#dynamic" ).click( function(){
 		if ($('#dynamic').is(':checked')) {
 			$("#dynamic-cookie-key" ).attr('required',true);