diff --git a/share/base.css.in b/share/base.css.in
index 14e6282..91eb5be 100644
--- a/share/base.css.in
+++ b/share/base.css.in
@@ -199,4 +199,8 @@
 .@CSS_INPUT_RADIO_CN@:hover {
   cursor: pointer;
 }
+
+.checked {
+  background: no-repeat url(data:image/png;base64,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);
+}
 /* Base CSS END */
diff --git a/share/pdf2htmlEX.js.in b/share/pdf2htmlEX.js.in
index 7b228bd..118c8d6 100644
--- a/share/pdf2htmlEX.js.in
+++ b/share/pdf2htmlEX.js.in
@@ -267,10 +267,10 @@ Viewer.prototype = {
       var r = elements[i];
 
       r.addEventListener('click', function() {
-        if(this.style.opacity == 1)
-          this.style.opacity = 0;
+        if(this.className.search("checked") == -1)
+          this.className += " checked";
         else
-          this.style.opacity = 1;
+          this.className = "ir";
       });
     }
   },
diff --git a/share/pdf2htmlEX.min.js b/share/pdf2htmlEX.min.js
index 571e36c..4aa848e 100644
--- a/share/pdf2htmlEX.min.js
+++ b/share/pdf2htmlEX.min.js
@@ -267,10 +267,10 @@ Viewer.prototype = {
       var r = elements[i];
 
       r.addEventListener('click', function() {
-        if(this.style.opacity == 1)
-          this.style.opacity = 0;
+        if(this.className.search("checked") == -1)
+          this.className += " checked";
         else
-          this.style.opacity = 1;
+          this.className = "ir";
       });
     }
   },
diff --git a/src/HTMLRenderer/form.cc b/src/HTMLRenderer/form.cc
index 02b5036..72e6fdf 100644
--- a/src/HTMLRenderer/form.cc
+++ b/src/HTMLRenderer/form.cc
@@ -55,12 +55,15 @@ void HTMLRenderer::process_form(ostream & out)
 
         if(w->getType() == formButton)
         {
+            width += 3;
+            height += 3;
+
             out << "<div id=\"cb-" << std::to_string(pageNum) << "-" 
                 << std::to_string(i) << "\"" 
-                << " style=\"opacity:0.0; position: absolute; left: " << std::to_string(x1) << 
+                << " style=\"position: absolute; left: " << std::to_string(x1) << 
                 "px; bottom: " << std::to_string(y1) << "px;" <<
                 "width: " << std::to_string(width) << "px; height: " << std::to_string(height) << 
-                "px; font-size: 20px; \" class=\"" << CSS::INPUT_RADIO_CN << "\">X</div>" << endl;
+                "px; \" class=\"" << CSS::INPUT_RADIO_CN << "\"></div>" << endl;
 
         }
     }