<STYLE>
.img_sina_share {
DISPLAY: none; CURSOR: pointer; POSITION: absolute
}
.img_qq_share {
DISPLAY: none; CURSOR: pointer; POSITION: absolute
}
</STYLE>
<IMG 
class=img_sina_share id=imgSinaShare title=将选中内容分享到新浪微博 
src="http://www.068i.com/template/weibo/image/sina.gif">
<IMG 
class=img_qq_share id=imgQqShare title=将选中内容分享到腾讯微博 
src="http://www.068i.com/template/weibo/image/QQweibo.gif">
<SCRIPT>
var eleImgShare = document.getElementById("imgSinaShare"); //新浪微博图标
var eleImgShare2 = document.getElementById("imgQqShare"); //腾讯微博图标

var $miniBlogShare = function(eleShare,eleShare2,eleContainer) { //实现方法
var eleTitle = document.getElementsByTagName("title")[0];
eleContainer = eleContainer || document;
var funGetSelectTxt = function() { //获取选中文字
var txt = "";
if(document.selection) {
txt = document.selection.createRange().text; // IE
} else {
txt = document.getSelection();
}
return txt.toString();
};
eleContainer.onmouseup = function(e) { //限定容器若有文字被选中
e = e || window.event;
var txt = funGetSelectTxt(), sh = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop || 0;
var left = (e.clientX - 40 < 0) ? e.clientX + 20 : e.clientX - 40, top = (e.clientY - 40 < 0) ? e.clientY + sh + 20 : e.clientY + sh - 40;
if (txt) {
eleShare.style.display = "inline";
eleShare.style.left = left + "px";
eleShare.style.top = top + "px";
eleShare2.style.display = "inline";
eleShare2.style.left = left + 30 + "px";
eleShare2.style.top = top + "px";
} else {
eleShare.style.display = "none";
eleShare2.style.display = "none";
}
};
eleShare.onclick = function() { //点击新浪微博图标
var txt = funGetSelectTxt(), title = (eleTitle && eleTitle.innerHTML)? eleTitle.innerHTML : "未命名页面";
if (txt) {
window.open('http://v.t.sina.com.cn/share/share.php?title=' + txt + '→来自页面"' + title + '"的文字片段&url=' + window.location.href); 
}
};
eleShare2.onclick = function() { //点击腾讯微博图标
var txt = funGetSelectTxt(), title = (eleTitle && eleTitle.innerHTML)? eleTitle.innerHTML : "未命名页面";
if (txt) {
window.open( 'http://v.t.qq.com/share/share.php?title=' + encodeURIComponent(txt + '→来自页面"' + title + '"的文字片段&url=' + window.location.href)); 
}
};
}(eleImgShare,eleImgShare2);
</SCRIPT>

转自https://www.discuz.net/thread-2077854-1-1.html