全角字符数字转换为半角字符数字
function CtoH(str){
var result="";
for (var i = 0; i < str.length; i++){
if (str.charCodeAt(i)==12288){
result+= String.fromCharCode(str.charCodeAt(i)-12256);
continue;
}
if (str.charCodeAt(i)>65280 && str.charCodeAt(i)<65375)
result+= String.fromCharCode(str.charCodeAt(i)-65248);
else
result+= String.fromCharCode(str.charCodeAt(i));
}
console.log(result);
return result;
}