Js Form Verification Method (practical) _ form special effects

Every time we use form verification, we are looking for something everywhere, and many of them are useless on the Internet. I finally accumulated these methods. Some of the methods used in my program are certainly easy to use, mainly using simple regular expressions for judgment. If you have any bugs, please submit them. // The verification below is the length
Function checkTextLen (textId ){
Var len = 0;
Var checkField = document. getElementById (textId );
Var inputstring = checkField. value;
Var string_length = inputstring. length;
If (string_length = 0)
{
Return 0;
}
For (var I = 0; I {
If (inputstring. charAt (I). charCodeAt ()> 255) len + = 2;
Else len + = 1;
}
Return len;
}
Function checkTextLength (textId, length, msg ){
Var textObj = document. getElementById (textId );
If (checkTextLen (textId)> length/1 ){
Alert ("[" + msg + "]" + "maximum length" + length + "bit," + "Please input again! Note: One Chinese Character occupies 2 places ");
TextObj. focus ();
Return false;
} Else {
Return true;
}
}
// The verification below does not contain invalid characters, including Chinese characters, English letters, and numbers.
Function isValidString (textId, errMsg ){
SzStr = document. getElementById (textId). value;
VoidChar = "'\"> <'~! @ # $ % ^ &\(\)()! ￥ ......?? "" '* ";
For (I = 0; I <voidChar. length; I ++ ){
AChar = voidChar. substring (I, I + 1 );
If (szStr. indexOf (aChar)>-1 ){
Alert (errMsg );
Return false;
}
}
Return true;
}
// Only letters, numbers, and underscores can be entered for verification below
Function isEnglish (textId, errMsg)
{
S = document. getElementById (textId). value;
// The length of the following regular expression is between 6 and 20
// Var patrn =/^ (\ w) {6, 20} $ /;
Var patrn =/^ (\ w) * $ /;
If (! Patrn.exe c (s )){
Alert (errMsg );
Return false
}
Return true
}
// The following verification only allows Chinese Characters
Function isChinese (textId, errMsg)
{
S = document. getElementById (textId). value;
Var patrn =/[^ \ u4E00-\ u9FA5]/g;
If (patrn.exe c (s )){
Alert (errMsg );
Return false
}
Return true
}
// The following verification only allows numbers
Function isNumber (textId, errMsg)
{
S = document. getElementById (textId). value;
// The length of the following regular expression is between 6 and 20
// Var patrn =/^ (\ d) {6, 20} $ /;
Var patrn =/^ (\ d) * $ /;
If (! Patrn.exe c (s )){
Alert (errMsg );
Return false
}
Return true
}
The Regular Expression in Javascript is used to control whether non-numbers can be entered in the text box, that is, only numbers can be entered. Call method: onkeyup = "onlyNum (this );"
Function onlyNum (obj)
{
Temp = obj. value;
// Note the regular expression below, which is not enclosed by quotation marks ..
Obj. value = temp. replace (/\ D/g ,'');
}