JS method to determine whether the input string is a number (regular expression)

Examples are as follows:

if (!checkNumber(gopage_val)) {
  alert("请输入正确页数(数字)");
  return false;
 }
 
 
 
 
//验证字符串是否是数字
function checkNumber(theObj) {
  var reg = /^[0-9]+.?[0-9]*$/;
  if (reg.test(theObj)) {
    return true;
  }
  return false;
}