javascript 中的utf-8 与 中文的互转

<SCRIPT LANGUAGE="JavaScript">
<!--
function EncodeUtf8(s1)
{
var s = escape(s1);
var sa = s.split("%");
var retV ="";
if(sa[0] != "")
{
retV = sa[0];
}
for(var i = 1; i < sa.length; i ++)
{
if(sa[i].substring(0,1) == "u")
{
retV += Hex2Utf8(Str2Hex(sa[i].substring(1,5)));

}
else retV += "%" + sa[i];
}

return retV;
}
function Str2Hex(s)
{
var c = "";
var n;
var ss = "0123456789ABCDEF";
var digS = "";
for(var i = 0; i < s.length; i ++)
{
c = s.charAt(i);
n = ss.indexOf(c);
digS += Dec2Dig(eval(n));

}
//return value;
return digS;
}
function Dec2Dig(n1)
{
var s = "";
var n2 = 0;
for(var i = 0; i < 4; i++)
{
n2 = Math.pow(2,3 - i);
if(n1 >= n2)
{
s += '1';
n1 = n1 - n2;
}
else
s += '0';

}
return s;

}
function Dig2Dec(s)
{
var retV = 0;
if(s.length == 4)
{
for(var i = 0; i < 4; i ++)
{
retV += eval(s.charAt(i)) * Math.pow(2, 3 - i);
}
return retV;
}
return -1;
}
function Hex2Utf8(s)
{
var retS = "";
var tempS = "";
var ss = "";
if(s.length == 16)
{
tempS = "1110" + s.substring(0, 4);
tempS += "10" + s.substring(4, 10);
tempS += "10" + s.substring(10,16);
var sss = "0123456789ABCDEF";
for(var i = 0; i < 3; i ++)
{
retS += "%";
ss = tempS.substring(i * 8, (eval(i)+1)*8);



retS += sss.charAt(Dig2Dec(ss.substring(0,4)));
retS += sss.charAt(Dig2Dec(ss.substring(4,8)));
}
return retS;
}
return "";
}

function revertUTF8(szInput)
{
var x,wch,wch1,wch2,uch="",szRet="";
for (x=0; x<szInput.length; x++)
{
if (szInput.charAt(x)=="%")
{
wch =parseInt(szInput.charAt(++x) + szInput.charAt(++x),16);
if (!wch) {break;}
if (!(wch & 0x80))
{
wch = wch;
}
else if (!(wch & 0x20))
{
x++;
wch1 = parseInt(szInput.charAt(++x) + szInput.charAt(++x),16);
wch = (wch & 0x1F)<< 6;
wch1 = wch1 & 0x3F;
wch = wch + wch1;
}
else
{
x++;
wch1 = parseInt(szInput.charAt(++x) + szInput.charAt(++x),16);
x++;
wch2 = parseInt(szInput.charAt(++x) + szInput.charAt(++x),16);
wch = (wch & 0x0F)<< 12;
wch1 = (wch1 & 0x3F)<< 6;
wch2 = (wch2 & 0x3F);
wch = wch + wch1 + wch2;
}
szRet += String.fromCharCode(wch);
}
else
{
szRet += szInput.charAt(x);
}
}
return(szRet);
}

document.write(EncodeUtf8("夺载基本原理"));
document.write(revertUTF8("%E5%A4%BA%E8%BD%BD%E5%9F%BA%E6%9C%AC%E5%8E%9F%E7%90%86"));

//-->
</SCRIPT>