diff --git a/dist/highlightjs-copy-button.min.js b/dist/highlightjs-copy-button.min.js
index 3598a6b..1854ba6 100644
--- a/dist/highlightjs-copy-button.min.js
+++ b/dist/highlightjs-copy-button.min.js
@@ -1,2 +1,2 @@
 /*! highlightjs-copy-button v1.0.5 */
-(function(i){var h="hljs-button",j="hljs-ln-code",a="Copy",e="Error",d="Copied";String.prototype.format=String.prototype.f=function(){var l=arguments;return this.replace(/\{(\d+)\}/g,function(o,p){return l[p]?l[p]:o})};if(typeof i.hljs==="undefined"){console.error("highlight.js not detected!")}else{i.hljs.initCopyButtonOnLoad=f;i.hljs.addCopyButton=k;i.hljs.copyCode=g;c()}function g(n){var o=n.target||n.srcElement;if(o.className===h){n.preventDefault();var l=document.getElementById("post-id-target");if(!l){l=document.createElement("textarea");l.style.position="absolute";l.style.left="-9999px";l.style.top="0";l.id="hljs-copy-el";document.body.appendChild(l)}l.textContent=n.currentTarget.innerText;l.select();try{var p=document.execCommand("copy");o.dataset.title=p?d:e;if(p){setTimeout(function(){o.dataset.title=a},2000)}}catch(m){o.dataset.title=e}}}function c(){var l=document.createElement("style");l.type="text/css";l.innerHTML=([".hljs{position: relative}",".hljs:hover .{0}{display: block}",".{0}{","display: none;","position: absolute;","right: 0;","top: 0;","background-color: white;","padding: 2px 10px;","margin: 3px;","border-radius: 5px;","border: 1px solid darkgray;","cursor: pointer;","box-shadow: 0 1px 1px rgba(0,0,0,0.12), 0 1px 1px rgba(0,0,0,0.24);","}",".{0}:after{","content: attr(data-title)","}"].join("")).format(h);document.getElementsByTagName("head")[0].appendChild(l)}function f(){if(document.readyState==="complete"){b()}else{i.addEventListener("DOMContentLoaded",b)}}function b(){try{var n=document.querySelectorAll("code.hljs");for(var l in n){if(n.hasOwnProperty(l)){k(n[l])}}}catch(m){console.error("CopyButton error: ",m)}}function k(l){if(typeof l!=="object"){return}l.innerHTML=l.innerHTML+('<div class="{0}" data-title="{1}"></div>').format(h,a);l.setAttribute("onclick","hljs.copyCode(event)")}}(window));
\ No newline at end of file
+(function(w){var BLOCK_NAME="hljs-button",LN_CLASS="hljs-ln-code",TEXT_COPY="Copy",TEXT_ERROR="Error",TEXT_COPIED="Copied";String.prototype.format=String.prototype.f=function(){var args=arguments;return this.replace(/\{(\d+)\}/g,function(m,n){return args[n]?args[n]:m})};if(typeof w.hljs==="undefined"){console.error("highlight.js not detected!")}else{w.hljs.initCopyButtonOnLoad=onLoad;w.hljs.addCopyButton=addCopyButton;w.hljs.copyCode=copyCode;addStyles()}function copyCode(event){var target=event.target||event.srcElement,scrolltop=document.documentElement.scrollTop;if(target.className===BLOCK_NAME){event.preventDefault();var el=document.getElementById("post-id-target");if(!el){el=document.createElement("textarea");el.style.position="absolute";el.style.left="-9999px";el.style.top=scrolltop+"px";el.id="hljs-copy-el";document.body.appendChild(el)}el.textContent=event.currentTarget.innerText;el.select();try{var successful=document.execCommand("copy");target.dataset.title=successful?TEXT_COPIED:TEXT_ERROR;if(successful){setTimeout(function(){target.dataset.title=TEXT_COPY},2000)}}catch(err){target.dataset.title=TEXT_ERROR}}}function addStyles(){var css=document.createElement("style");css.type="text/css";css.innerHTML=(["pre{position: relative}","pre:hover .{0}{display: block}",".{0}{","display: none;","position: absolute;","right: 0;","top: 0;","background-color: white;","padding: 2px 10px;","margin: 3px;","border-radius: 5px;","border: 1px solid darkgray;","cursor: pointer;","box-shadow: 0 1px 1px rgba(0,0,0,0.12), 0 1px 1px rgba(0,0,0,0.24);","}",".{0}:after{","content: attr(data-title)","}"].join("")).format(BLOCK_NAME);document.getElementsByTagName("head")[0].appendChild(css)}function onLoad(){if(document.readyState==="complete"){documentReady()}else{w.addEventListener("DOMContentLoaded",documentReady)}}function documentReady(){try{var blocks=document.querySelectorAll("code.hljs");for(var i in blocks){if(blocks.hasOwnProperty(i)){addCopyButton(blocks[i].parentNode)}}}catch(e){console.error("CopyButton error: ",e)}}function addCopyButton(element){if(typeof element!=="object"){return}element.innerHTML=element.innerHTML+('<div class="{0}" data-title="{1}"></div>').format(BLOCK_NAME,TEXT_COPY);element.setAttribute("onclick","hljs.copyCode(event)")}}(window));
\ No newline at end of file
diff --git a/src/highlightjs-copy-button.js b/src/highlightjs-copy-button.js
index 6736086..d4bfc1e 100644
--- a/src/highlightjs-copy-button.js
+++ b/src/highlightjs-copy-button.js
@@ -27,7 +27,8 @@
     }
 
     function copyCode(event) {
-        var target = event.target || event.srcElement;
+        var target = event.target || event.srcElement,
+            scrolltop = document.documentElement.scrollTop; // firefox get scrollTop,chrome Unable to get,
         if (target.className === BLOCK_NAME) {
             event.preventDefault();
 
@@ -36,7 +37,7 @@
                 el = document.createElement("textarea");
                 el.style.position = "absolute";
                 el.style.left = "-9999px";
-                el.style.top = "0";
+                el.style.top = scrolltop + 'px';
                 el.id = 'hljs-copy-el';
                 document.body.appendChild(el);
             }
@@ -61,8 +62,8 @@
         var css = document.createElement('style');
         css.type = 'text/css';
         css.innerHTML = ( [
-            '.hljs{position: relative}',
-            '.hljs:hover .{0}{display: block}',
+            'pre{position: relative}',
+            'pre:hover .{0}{display: block}',
             '.{0}{',
             'display: none;',
             'position: absolute;',
@@ -97,7 +98,7 @@
 
             for (var i in blocks) {
                 if (blocks.hasOwnProperty(i)) {
-                    addCopyButton(blocks[i]);
+                    addCopyButton(blocks[i].parentNode);
                 }
             }
         } catch (e) {