字符串中提取有用的字符问题
想把下面的中文部分提取出来，不知道怎么操作，请高手回答给出代码，谢了
<ul>
<li><span id='fld000000061' onclick='openFolder("000000061")'><img src='/images/pui-plus.gif' style='position: relative;top:-6px'/><img src='/images/ftv2folderclosed.gif'/></span><span onclick='jumpTo("00000006")' style='position: relative;top:-6px'>第一章 请卹事实</span></li>
<ul id='idoc000000061' style='display:none'>
 <li><span id='idoc000000062' onclick=''><img src='/images/pui-norm.gif' style='position: relative;top:-6px'></img><img src='/images/ftv2folderclosed.gif' ></img></span><span onclick='jumpTo("00000006")' style='position: relative;top:-6px'>第一节 公务员伤亡及退职请卹事实</span></li>
<ul id='iblock000000062' style='display:none'>
</ul>
 <li><span id='idoc000000074' onclick=''><img src='/images/pui-norm.gif' style='position: relative;top:-6px'></img><img src='/images/ftv2folderclosed.gif' ></img></span><span onclick='jumpTo("00000007")' style='position: relative;top:-6px'>第二节 陆军伤亡请卹事实</span></li>
<ul id='iblock000000074' style='display:none'>
</ul>
 <li><span id='idoc000000106' onclick=''><img src='/images/pui-norm.gif' style='position: relative;top:-6px'></img><img src='/images/ftv2folderclosed.gif' ></img></span><span onclick='jumpTo("00000010")' style='position: relative;top:-6px'>第三节 空军伤亡请卹事实</span></li>
<ul id='iblock000000106' style='display:none'>
</ul>
 <li><span id='idoc000000138' onclick=''><img src='/images/pui-norm.gif' style='position: relative;top:-6px'></img><img src='/images/ftv2folderclosed.gif' ></img></span><span onclick='jumpTo("00000013")' style='position: relative;top:-6px'>第四节 人民守土伤亡请卹事实</span></li>
<ul id='iblock000000138' style='display:none'>
</ul>
</ul>
<li><span id='fld000000143' onclick='openFolder("000000143")'><img src='/images/pui-plus.gif' style='position: relative;top:-6px'/><img src='/images/ftv2folderclosed.gif'/></span><span onclick='jumpTo("00000014")' style='position: relative;top:-6px'>第二章 请卹手续</span></li>
<ul id='idoc000000143' style='display:none'>
 <li><span id='idoc000000142' onclick=''><img src='/images/pui-norm.gif' style='position: relative;top:-6px'></img><img src='/images/ftv2folderclosed.gif' ></img></span><span onclick='jumpTo("00000014")' style='position: relative;top:-6px'>第一节 公务员伤亡及退职请卹手续</span></li>
<ul id='iblock000000142' style='display:none'>
</ul>
 <li><span id='idoc000000154' onclick=''><img src='/images/pui-norm.gif' style='position: relative;top:-6px'></img><img src='/images/ftv2folderclosed.gif' ></img></span><span onclick='jumpTo("00000015")' style='position: relative;top:-6px'>第二节 陆空军伤亡请卹手续</span></li>
<ul id='iblock000000154' style='display:none'>
</ul>
 <li><span id='idoc000000176' onclick=''><img src='/images/pui-norm.gif' style='position: relative;top:-6px'></img><img src='/images/ftv2folderclosed.gif' ></img></span><span onclick='jumpTo("00000017")' style='position: relative;top:-6px'>第三节 人民守土伤亡请卹手续</span></li>
<ul id='iblock000000176' style='display:none'>
</ul>
</ul>
<li><span id='fld000000185' onclick='openFolder("000000185")'><img src='/images/pui-plus.gif' style=