匹配不大于99.99的数字的正则表达式

<span style="font-family:punctuation, 微软雅黑, Tohoma;"><span style="font-size: 14px; line-height: 22px;">上次发的正则有点小问题 这次修改后重发</span></span>

<span style="font-family: punctuation, 微软雅黑, Tohoma; font-size: 14px; line-height: 22px;">^[0]*?(?:99(?:\.(?:[0-8]\d*|9(?:[0-8]\d*)?|99[0]*))?|(?:[0-8]?\d|9[0-8])(?:\.\d+)?)$</span>

var checkText = function() {
var reg = /^[0]*?(?:99(?:\.(?:[0-8]\d*|9(?:[0-8]\d*)?|99[0]*))?|(?:[0-8]?\d|9[0-8])(?:\.\d+)?)$/g;
if ($('content').value == "") {
$('content').value = "请输入不大于99.99的数字";
$('desc').innerHTML = "";
} else {
if (!(reg.test($('content').value))) {
$('desc').innerHTML = "输入有误,请重新输入!";
$('content').value = "请输入不大于99.99的数字";
} else {
$('desc').innerHTML = "输入正确!";
$('content').value=$('content').value.replace(/^0*(.*)/g,"$1").replace(/(.*?\..*?)0*$/g,"$1");
}
}
}