控制文本框只输入正负浮点数

function validateNumber(e, pnumber) {
var pFloat = /^\d+[.]?\d*$/;
if (!pFloat.test(pnumber)) {
var newValue = pFloat.exec(e.value);
if (newValue != null) {
e.value = newValue;
}
else {
e.value = "";
}
}
return false;
}

$(document).ready(function () {
var objWay1 = "<%=txtWay1.ClientID %>";
var way1;
$("#" + objWay1).keyup(function () {
var tag = 0;
way1 = $("#" + objWay1).val();
if (way1 != "-") {
if (way1.indexOf("-") > -1) {
way1 = way1.replace("-", "");
tag = 1;
}
validateNumber(this, way1);
if(way1.indexOf('.')>0)way1="";
way1 = (way1 == "") ? 0.000 : (tag == 0 ? way1 : parseFloat(-way1));
alert(way1);
}
});

});