JavaScript form validation can only enter decimals ...

      about form validation, it is best to use regular expressions, of course, if the simple do not bother to write regular expressions, in general, use the Internet to search a lot of regular expressions, all kinds of, everything, The following example is a sample of JavaScript validation input decimal values: function Isfunkey (code) { //8--> backspace //--> end // ; home //Notoginseng--> left arrow //--> right arrow //--> delete //112~123--> F1~F12   var Funkeys = [8, N, Panax Notoginseng, 46];  for (var i = 112; I <= 123; i++) {  Funkeys.push (i); }&NB Sp for (var i = 0; i < funkeys.length i++) {  if (funkeys[i] = = code) {  return true; } }  retur N false; }  function GetChar (k) {  if (k >= && k <=) {  return String.fromCharCode (k); }  if (k >= && k <=) {  return String.fromCharCode (k-48); }  if (k = = 110 | | K = = 190 | | k== 188) {  return ".";  }  if (k = = 109 | | k = = 189) {  return "-"; }  if (k = = | | k = = 187) {  return "+";nbsp }  return "#"; }        In short, JavaScript verifies the form, uses the encoded values of each character, and then combines logical judgments, which are not difficult to write.