mention date search parameter in search option help (index.html)

htroot/index.html

@@ -149,6 +149,12 @@
           <dd>only pages with as-author-anotated &lt;author&gt;</dd>
           <dt>tld:&lt;tld&gt;</dt>
           <dd>only pages from top-level-domains &lt;tld&gt;</dd>
+          #(datesincontent)#::
+            <dt>on:&lt;date&gt;</dt>
+            <dd>only pages with &lt;date&gt; in content</dd>
+            <dt>from:&lt;date1&gt; to:&lt;date2&gt;</dt>
+            <dd>only pages with a date between &lt;date1&gt; and &lt;date2&gt; in content</dd>
+          #(/datesincontent)#
           <dt>/http</dt>
           <dd>only resources from http or https servers</dd>
           <dt>/ftp</dt>

htroot/index.java

@@ -33,6 +33,7 @@ import net.yacy.cora.document.analysis.Classification.ContentDomain;
 import net.yacy.cora.protocol.RequestHeader;
 import net.yacy.search.Switchboard;
 import net.yacy.search.SwitchboardConstants;
+import net.yacy.search.schema.CollectionSchema;
 import net.yacy.server.serverObjects;
 import net.yacy.server.serverSwitch;
 
@@ -65,9 +66,11 @@ public class index {
         int searchoptions = (post == null) ? 0 : Math.min(1, post.getInt("searchoptions", 0));
         if (!sb.getConfigBool("search.options", true)) {
             searchoptions = 0;
-        } else { // show heuristic hint on search option screen
-            // (only if heuristic is ON by config)
+        } else { 
+            // show heuristic hint on search option screen (only if heuristic is ON by config)
             prop.put("searchoptions_heuristic", sb.getConfigBool(SwitchboardConstants.HEURISTIC_OPENSEARCH, false));
+            // show date search options (only if dates_in_content_dts search target field is active)
+            prop.put("searchoptions_datesincontent", sb.index.fulltext().getDefaultConfiguration().contains(CollectionSchema.dates_in_content_dts));
         }
         final String former = (post == null) ? "" : post.get("former", "");
         final int count = Math.min(100, (post == null) ? 10 : post.getInt("count", 10));

locales/master.lng.xlf

@@ -10600,6 +10600,12 @@
     <trans-unit id="e5eb9948" xml:space="preserve" approved="no" translate="yes">
        <source>only pages from top-level-domains</source>
     </trans-unit>
+    <trans-unit id="6b8b308b" xml:space="preserve" approved="no" translate="yes">
+       <source>only pages with a date between &amp;lt;date1&amp;gt; and &amp;lt;date2&amp;gt; in content</source>
+    </trans-unit>
+    <trans-unit id="7fae2eb1" xml:space="preserve" approved="no" translate="yes">
+       <source>only pages with &amp;lt;date&amp;gt; in content</source>
+    </trans-unit>    
     <trans-unit id="f0ec5b4f" xml:space="preserve" approved="no" translate="yes">
        <source>only resources from http or https servers</source>
     </trans-unit>