--- a/svghmi/gen_index_xhtml.xslt	Tue May 26 09:58:20 2020 +0200
+++ b/svghmi/gen_index_xhtml.xslt	Tue May 26 10:53:02 2020 +0200
@@ -1152,40 +1152,72 @@
     <xsl:text>}
 </xsl:text>
   </xsl:template>
-  <xsl:template mode="widget_class" match="widget[@type='Button']">
-    <xsl:text>class ButtonWidget extends Widget{
-</xsl:text>
-    <xsl:text>    frequency = 5;
-</xsl:text>
-    <xsl:text>    init() {
-</xsl:text>
-    <xsl:text>        // TODO : use attributes to allow interaction through svg:use
-</xsl:text>
-    <xsl:text>        // TODO : deal with dragging
-</xsl:text>
-    <xsl:text>        this.element.addEventListener(
-</xsl:text>
-    <xsl:text>          "mousedown",
-</xsl:text>
-    <xsl:text>          evt =&gt; {
-</xsl:text>
-    <xsl:text>              change_hmi_value(this.indexes[0], "=1");
-</xsl:text>
-    <xsl:text>          });
-</xsl:text>
-    <xsl:text>        this.element.addEventListener(
-</xsl:text>
-    <xsl:text>          "mouseup",
-</xsl:text>
-    <xsl:text>          evt =&gt; {
-</xsl:text>
-    <xsl:text>              change_hmi_value(this.indexes[0], "=0");
-</xsl:text>
-    <xsl:text>          });
+  <xsl:template mode="widget_defs" match="widget[@type='Button']">
+    <xsl:param name="hmi_element"/>
+    <xsl:call-template name="defs_by_labels">
+      <xsl:with-param name="hmi_element" select="$hmi_element"/>
+      <xsl:with-param name="labels">
+        <xsl:text>active inactive</xsl:text>
+      </xsl:with-param>
+      <xsl:with-param name="mandatory" select="'no'"/>
+    </xsl:call-template>
+    <xsl:text>frequency: 5,
+</xsl:text>
+    <xsl:text>on_mouse_down: function(evt) {
+</xsl:text>
+    <xsl:text>    if (this.active_style &amp;&amp; this.inactive_style) {
+</xsl:text>
+    <xsl:text>        this.active_elt.setAttribute("style", this.active_style);
+</xsl:text>
+    <xsl:text>        this.inactive_elt.setAttribute("style", "display:none");
 </xsl:text>
     <xsl:text>    }
 </xsl:text>
-    <xsl:text>}
+    <xsl:text>    change_hmi_value(this.indexes[0], "=1");
+</xsl:text>
+    <xsl:text>},
+</xsl:text>
+    <xsl:text>on_mouse_up: function(evt) {
+</xsl:text>
+    <xsl:text>    if (this.active_style &amp;&amp; this.inactive_style) {
+</xsl:text>
+    <xsl:text>        this.active_elt.setAttribute("style", "display:none");
+</xsl:text>
+    <xsl:text>        this.inactive_elt.setAttribute("style", this.inactive_style);
+</xsl:text>
+    <xsl:text>    }
+</xsl:text>
+    <xsl:text>    change_hmi_value(this.indexes[0], "=0");
+</xsl:text>
+    <xsl:text>},
+</xsl:text>
+    <xsl:text>active_style: undefined,
+</xsl:text>
+    <xsl:text>inactive_style: undefined,
+</xsl:text>
+    <xsl:text>init: function() {
+</xsl:text>
+    <xsl:text>  this.active_style = this.active_elt ? this.active_elt.style.cssText : undefined;
+</xsl:text>
+    <xsl:text>  this.inactive_style = this.inactive_elt ? this.inactive_elt.style.cssText : undefined;
+</xsl:text>
+    <xsl:text>  if (this.active_style &amp;&amp; this.inactive_style) {
+</xsl:text>
+    <xsl:text>      this.active_elt.setAttribute("style", "display:none");
+</xsl:text>
+    <xsl:text>      this.inactive_elt.setAttribute("style", this.inactive_style);
+</xsl:text>
+    <xsl:text>  }
+</xsl:text>
+    <xsl:text>  this.element.setAttribute("onmousedown", "hmi_widgets['</xsl:text>
+    <xsl:value-of select="$hmi_element/@id"/>
+    <xsl:text>'].on_mouse_down(evt)");
+</xsl:text>
+    <xsl:text>  this.element.setAttribute("onmouseup", "hmi_widgets['</xsl:text>
+    <xsl:value-of select="$hmi_element/@id"/>
+    <xsl:text>'].on_mouse_up(evt)");
+</xsl:text>
+    <xsl:text>},
 </xsl:text>
   </xsl:template>
   <xsl:template mode="widget_defs" match="widget[@type='CircularBar']">
@@ -3271,8 +3303,6 @@
 </xsl:text>
           <xsl:text>    }
 </xsl:text>
-          <xsl:text>    console.log(opstr, given_val);
-</xsl:text>
           <xsl:text>    let old_val = cache[index];
 </xsl:text>
           <xsl:text>    let new_val;

--- a/svghmi/widget_button.ysl2	Tue May 26 09:58:20 2020 +0200
+++ b/svghmi/widget_button.ysl2	Tue May 26 10:53:02 2020 +0200
@@ -1,20 +1,33 @@
 // widget_button.ysl2
 
-template "widget[@type='Button']", mode="widget_class"
-    ||
-    class ButtonWidget extends Widget{
-        frequency = 5;
-        init() {
-            this.element.addEventListener(
-              "mousedown",
-              evt => {
-                  change_hmi_value(this.indexes[0], "=1");
-              });
-            this.element.addEventListener(
-              "mouseup",
-              evt => {
-                  change_hmi_value(this.indexes[0], "=0");
-              });
-        }
-    }
-    ||
+template "widget[@type='Button']", mode="widget_defs" {
+    param "hmi_element";
+    optional_labels("active inactive");
+    | frequency: 5,
+    | on_mouse_down: function(evt) {
+    |     if (this.active_style && this.inactive_style) {
+    |         this.active_elt.setAttribute("style", this.active_style);
+    |         this.inactive_elt.setAttribute("style", "display:none");
+    |     }
+    |     change_hmi_value(this.indexes[0], "=1");
+    | },
+    | on_mouse_up: function(evt) {
+    |     if (this.active_style && this.inactive_style) {
+    |         this.active_elt.setAttribute("style", "display:none");
+    |         this.inactive_elt.setAttribute("style", this.inactive_style);
+    |     }
+    |     change_hmi_value(this.indexes[0], "=0");
+    | },
+    | active_style: undefined,
+    | inactive_style: undefined,
+    | init: function() {
+    |   this.active_style = this.active_elt ? this.active_elt.style.cssText : undefined;
+    |   this.inactive_style = this.inactive_elt ? this.inactive_elt.style.cssText : undefined;
+    |   if (this.active_style && this.inactive_style) {
+    |       this.active_elt.setAttribute("style", "display:none");
+    |       this.inactive_elt.setAttribute("style", this.inactive_style);
+    |   }
+    |   this.element.setAttribute("onmousedown", "hmi_widgets['«$hmi_element/@id»'].on_mouse_down(evt)");
+    |   this.element.setAttribute("onmouseup", "hmi_widgets['«$hmi_element/@id»'].on_mouse_up(evt)");
+    | },
+}
\ No newline at end of file