PHP生成的XML无效 - PHP generated XML not valid

我试图让jquery读取这个xml。jQuery运行成功函数，但不解析XML。我试着验证xml，得到找不到声明。谢谢。
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<prices>
  <pitch securityId="AUXNY" considerationCurrency="usd">
    <price actionIndicator="S" limit_kg="55970" limit_fmt_kg="55,970"/>
  </pitch>
  <pitch securityId="AUXNY" considerationCurrency="usd">
    <price actionIndicator="B" limit_kg="56000" limit_fmt_kg="56,000"/>
  </pitch>
  <pitch securityId="AUXLN" considerationCurrency="usd">
    <price actionIndicator="S" limit_kg="56020" limit_fmt_kg="56,020"/>
  </pitch>
  <pitch securityId="AUXLN" considerationCurrency="usd">
    <price actionIndicator="B" limit_kg="56260" limit_fmt_kg="56,260"/>
  </pitch>
  <pitch securityId="AUXZU" considerationCurrency="usd">
    <price actionIndicator="S" limit_kg="56150" limit_fmt_kg="56,150"/>
  </pitch>
  <pitch securityId="AUXZU" considerationCurrency="usd">
    <price actionIndicator="B" limit_kg="56390" limit_fmt_kg="56,390"/>
  </pitch>
  pitch securityId="AGXLN" considerationCurrency="usd">
    <price actionIndicator="S" limit_kg="1290" limit_fmt_kg="1,290"/>
  </pitch>
  <pitch securityId="AGXLN" considerationCurrency="usd">
    <price actionIndicator="B" limit_kg="1293" limit_fmt_kg="1,293"/>
  </pitch>
  <pitch securityId="AUXNY" considerationCurrency="gbp">
    <price actionIndicator="S" limit_kg="34390" limit_fmt_kg="34,390"/>
  </pitch>
  <pitch securityId="AUXNY" considerationCurrency="gbp">
    <price actionIndicator="B" limit_kg="34500" limit_fmt_kg="34,500"/>
  </pitch>
  <pitch securityId="AUXLN" considerationCurrency="gbp">
    <price actionIndicator="S" limit_kg="34420" limit_fmt_kg="34,420"/>
  </pitch>
  <pitch securityId="AUXLN" considerationCurrency="gbp">
    <price actionIndicator="B" limit_kg="34560" limit_fmt_kg="34,560"/>
  </pitch>
  <pitch securityId="AUXZU" considerationCurrency="gbp">
    <price actionIndicator="S" limit_kg="34310" limit_fmt_kg="34,310"/>
  </pitch>
  <pitch securityId="AUXZU" considerationCurrency="gbp">
    <price actionIndicator="B" limit_kg="34400" limit_fmt_kg="34,400"/>
  </pitch>
  <pitch securityId="AGXLN" considerationCurrency="gbp">
    <price actionIndicator="S" limit_kg="786" limit_fmt_kg="786"/>
  </pitch>
  <pitch securityId="AGXLN" considerationCurrency="gbp">
    <price actionIndicator="B" limit_kg="792" limit_fmt_kg="792"/>
  </pitch>
  <pitch securityId="AUXNY" considerationCurrency="eur">
    <price actionIndicator="S" limit_kg="39300" limit_fmt_kg="39,300"/>
  </pitch>
  <pitch securityId="AUXNY" considerationCurrency="eur">
    <price actionIndicator="B" limit_kg="39500" limit_fmt_kg="39,500"/>
  </pitch>
  <pitch securityId="AUXLN" considerationCurrency="eur">
    <price actionIndicator="S" limit_kg="39300" limit_fmt_kg="39,300"/>
  </pitch>
  <pitch securityId="AUXLN" considerationCurrency="eur">
    <price actionIndicator="B" limit_kg="39470" limit_fmt_kg="39,470"/>
  </pitch>
  <pitch securityId="AUXZU" considerationCurrency="eur">
    <price actionIndicator="S" limit_kg="39333" limit_fmt_kg="39,333"/>
  </pitch>
  <pitch securityId="AUXZU" considerationCurrency="eur">
    <price actionIndicator="B" limit_kg="39400" limit_fmt_kg="39,400"/>
  </pitch>
  <pitch securityId="AGXLN" considerationCurrency="eur">
    <price actionIndicator="S" limit_kg="893" limit_fmt_kg="893"/>
  </pitch>
  <pitch securityId="AGXLN" considerationCurrency="eur">
    <price actionIndicator="B" limit_kg="908" limit_fmt_kg="908"/>
  </pitch>
</prices>
尝试在jQuery ajax调用中将报头响应设置为内容类型text/xml，并将dataType设置为xml。