JS determines numbers, letters, and Chinese characters

1.

VaR Reg =/^ (\ w | [\ u4e00-\ u9fa5]) * $ /;
If (ARR = username. Match (REG ))
{
Ti = 1;
Return ture;
}
Else
{
Alert ("the user name can only contain English letters, numbers and Chinese characters. \ n check whether there are spaces or other symbols before and after ");
Ti = 0;
Return false;
}

2. Use regular expressions to restrict text box input in a webpage form:

You can only enter Chinese characters using regular expressions: onkeyup = "value = value. replace (/[^ \ u4e00-\ u9fa5]/g, '')" onbeforepaste = "clipboardData. setdata ('text', clipboardData. getdata ('text '). replace (/[^ \ u4e00-\ u9fa5]/g ,''))"

You can only enter the full-width characters: onkeyup = "value = value. replace (/[^ \ uff00-\ Uffff]/g, '')" onbeforepaste = "clipboardData. setdata ('text', clipboardData. getdata ('text '). replace (/[^ \ uff00-\ Uffff]/g ,''))"

Use a regular expression to limit that only numbers can be entered: onkeyup = "value = value. replace (/[^ \ D]/g, '')" onbeforepaste = "clipboardData. setdata ('text', clipboardData. getdata ('text '). replace (/[^ \ D]/g ,''))"

You can only enter numbers and English letters using regular expressions: onkeyup = "value = value. replace (/[\ W]/g, '')" onbeforepaste = "clipboardData. setdata ('text', clipboardData. getdata ('text '). replace (/[^ \ D]/g ,''))"

Number
<SCRIPT>
Function check ()
{
If (! Isnan (document. All. Form. Str. Value ))
{
Alert ("Number ");
}
</SCRIPT>
Letter
<SCRIPT>
Function check ()
{
VaR STR =/[_ A-Za-Z]/;
If (Str. Test (document. All. Form. Str. Value ))
{
Alert ("letter ");
}
}
</SCRIPT>
<Form name = "form" Action = "" onsubmit = "Return check ();">
<Input type = text name = STR>
<Input type = submit>
<Form>

---------------------------------------------------
/**
* Some Common JavaScript Functions (methods)
*
* For ease of use, all methods written as string objects
* Save it as a. js file to conveniently extend the function of a string object.
*
* Method name
*-------------------------------------------
* Trim deletes the first space.
* Occurs counts the number of times a specified character appears
* Isdigit checks whether it is composed of digits
* Isalpha checks whether the data is composed of digits, letters, and underscores.
* Check the number of isnumbers
* Lenb returns the number of bytes.
* Isinchinese check for Chinese Characters
* Simple isemail email check
* Isdate: A simple date check. A date object is returned successfully.
* Isinlist check whether there are character characters in the list
* Isinlist check whether there are character characters in the list
*/

/*** Delete spaces at the beginning and end ***/
String. Prototype. Trim = function (){
Return this. Replace (/(^ \ s *) | (\ s * $)/g ,"");
}

/*** Count the number of times a specified character appears ***/
String. Prototype. occurs = function (CH ){
// Var Re = eval ("/[^" + CH + "]/g ");
// Return this. Replace (Re, ""). length;
Return this. Split (CH). Length-1;
}

/*** Check whether the data is composed of digits ***/
String. Prototype. isdigit = function (){
VaR S = This. Trim ();
Return (S. Replace (/\ D/g, ""). Length = 0 );
}

/*** Check whether it is composed of digits, letters, and underscores ***/
String. Prototype. isalpha = function (){
Return (this. Replace (/\ W/g, ""). Length = 0 );
}
/*** Check the number of items ***/
String. Prototype. isnumber = function (){
VaR S = This. Trim ();
Return (S. Search (/^ [+-]? [0-9.] * $/)> = 0 );
}

/*** Number of returned bytes ***/
String. Prototype. lenb = function (){
Return this. Replace (/[^ \ x00-\ xFF]/g, "**"). length;
}

/*** Check whether Chinese characters are contained ***/
String. Prototype. isinchinese = function (){
Return (this. length! = This. Replace (/[^ \ x00-\ xFF]/g, "**"). Length );
}

/*** simple email check ***/
string. prototype. isemail = function () {
var strr;
var mail = This;
var Re =/(\ W + @ \ W + \. \ W + )(\. {0, 1} \ W *)(\. {0, 1} \ W *)/I;
re.exe C (Mail);
If (Regexp. $3! = "" & Regexp. $3! = "." & Regexp. $2! = ".")
strr = Regexp. $1 + Regexp. $2 + Regexp. $3;
else
If (Regexp. $2! = "" & Regexp. $2! = ". ")
strr = Regexp. $1 + Regexp. $2;
else
strr = Regexp. $1;
return (strr = Mail);
}

/*** Simple date check. The date object is returned successfully ***/
String. Prototype. isdate = function (){
VaR P;
VaR RE1 =/(\ D {4}) [year. /-] (\ D {1, 2}) [month. /-] (\ D {1, 2}) [Day]? $ /;
VaR re2 =/(\ D {1, 2}) [month. /-] (\ D {1, 2}) [Day. /-] (\ D {2}) [year]? $ /;
VaR RE3 =/(\ D {1, 2}) [month. /-] (\ D {1, 2}) [Day. /-] (\ D {4}) [year]? $ /;
If (re1.test (this )){
P = re1.exec (this );
Return new date (P [1], p [2], p [3]);
}
If (re2.test (this )){
P = re2.exec (this );
Return new date (P [3], p [1], p [2]);
}
If (re3.test (this )){
P = re3.exec (this );
Return new date (P [3], p [1], p [2]);
}
Return false;
}
/*** Check whether there are any character characters in the list ***/
String. Prototype. isinlist = function (list ){
VaR Re = eval ("/[" + list + "]/");
Return re. Test (this );
}

/// <Summary>
/// Only numbers are allowed
/// </Summary>
/// <Returns> if it is a number or letter, true is returned; otherwise, false is returned. </returns>
String. Prototype. isdigit = function ()
{
VaR Reg =/^ \ D + $/g;
Return Reg. Test (this );
}

/// <Summary>
/// Only numbers and letters are allowed
/// </Summary>
/// <Returns> if it is a number or letter, true is returned; otherwise, false is returned. </returns>
String. Prototype. isalphadigit = function ()
{
VaR Reg =/^ [a-zA-Z0-9] + $/g;
Return Reg. Test (this );
}

/// <Summary>
/// Only numbers, letters, and underscores are allowed
/// </Summary>
/// <Returns> if it is a number, letter, or underline, true is returned; otherwise, false is returned. </returns>
String. Prototype. isalpha = function ()
{
VaR Reg =/^ \ W + $/g;
Return Reg. Test (this );
}