The examples in this article summarize the commonly used validation functions for JavaScript. Share to everyone for your reference. The specific summary is as follows:
First, String class validation
1. Length Limit
Copy Code code as follows:
<script>
function test ()
{
if (DOCUMENT.A.B.VALUE.LENGTH>50)
{
Alert ("Cannot exceed 50 characters!") ");
Document.a.b.focus ();
return false;
}
}
</script>
<form name=a onsubmit= "return Test ()" >
<textarea name= "B" cols= "wrap=" "VIRTUAL" rows= "6" ></textarea>
<input type= "Submit" name= "Submit" value= "Check" >
</form>
2. Can only be Chinese characters
Copy Code code as follows:
<input onkeyup= "value="/oblog/value.replace (/[^/u4e00-/u9fa5]/g, ') ">
3. "Can only be English
Copy Code code as follows:
<script language=javascript>
function Onlyeng ()
{
if (!) ( EVENT.KEYCODE>=65&&EVENT.KEYCODE<=90))
Event.returnvalue=false;
}
</script>
<input onkeydown= "Onlyeng ();" >
4. Only the numbers
Copy Code code as follows:
<script language=javascript>
function Onlynum ()
{
if (!) ( (event.keycode>=48&&event.keycode<=57) | | (event.keycode>=96&&event.keycode<=105)))
Consider the number keys on the keypad
Event.returnvalue=false;
}
</script>
<input onkeydown= "Onlynum ();" >
5. Only English characters and numbers
Copy Code code as follows:
<input onkeyup= "value="/oblog/value.replace (/[/w]/g, "'") "onbeforepaste=" Clipboarddata.setdata (' text ', Clipboarddata.getdata (' text '). Replace (/[^/d]/g, ') ">
6. Verify the mailbox format
Copy Code code as follows:
<script Language=javascript runat=server>
function Isemail (stremail) {
if (Stremail.search (-/w+) | (/^/w+) | ( /./w+)) */@[a-za-z0-9]+ (/.| -) [a-za-z0-9]+] * *. [a-za-z0-9]+$/)!=-1)
return true;
Else
Alert ("Oh");
}
</SCRIPT>
<input type=text onblur=isemail (this.value) >
7. Shielding keywords (here shield * * * * and * * * *)
Copy Code code as follows:
<script language= "javascript1.2" >
function Test () {
if ((A.b.value.indexof ("* *") = = 0) | | (A.b.value.indexof ("* * *") = = 0)) {
Alert ("123");
A.b.focus ();
return false;}
}
</script>
<form name=a onsubmit= "return Test ()" >
<input Type=text name=b>
<input type= "Submit" name= "Submit" value= "Check" >
</form>
8. Two times input password is the same
Copy Code code as follows:
<form method=post action= "" >
<input type= "Password" id= "INPUT1" >
<input type= "Password" id= "Input2" >
<input type= "button" value= "Test" onclick= "Check ()" >
</FORM>
<script>
function Check ()
{
With (document.all) {
if (Input1.value!=input2.value)
{
Alert ("false")
Input1.value = "";
Input2.value = "";
}
else Document.forms[0].submit ();
}
}
</script>
9. Shielding right button is cool!
Copy Code code as follows:
Oncontextmenu= ' return false ' ondragstart= ' return false ' onselectstart= ' return false '
Added to the body.
Second, form verification
1 form items cannot be empty
Copy Code code as follows:
<script language= "JavaScript" >
<!--
function Checkform ()
{
if (Document.form.name.value.length = = 0) {
Alert ("Please enter your name!");
Document.form.name.focus ();
return false;
}
return true;
}
-->
</script>
2 Compare the values of two table items
Copy Code code as follows:
<script language= "JavaScript" >
<!--
function Checkform ()
if (Document.form.PWD.value!= document.form.PWD_Again.value) {
Alert ("The password you entered two times is different!") Please re-enter. ");
Document. ADDUser.PWD.focus ();
return false;
}
return true;
}
-->
</script>
3 form items can only be numbers and "_" for phone/bank account verification, can be extended to domain name registration, etc.
Copy Code code as follows:
<script language= "JavaScript" >
<!--
function Isnumber (String)
{
var letters = "1234567890-"; You can add your own input value
var i;
var C;
if (String.charat (0) = = '-')
return false;
if (String.charat (string.length-1) = = '-')
return false;
for (i = 0; i < string.length i + +)
{
c = String.charat (i);
if (Letters.indexof (c) < 0)
return false;
}
return true;
}
function Checkform ()
{
if (! Isnumber (Document.form.TEL.value)) {
Alert ("Your phone number is not legal!") ");
Document.form.TEL.focus ();
return false;
}
return true;
}
-->
</script>
4 table Single input value/length limit
Copy Code code as follows:
<script language= "JavaScript" >
<!--
function Checkform ()
{
if (Document.form.count.value > | | Document.form.count.value < 1)
{
Alert ("The input value cannot be less than 0 or greater than 100!");
Document.form.count.focus ();
return false;
}
if (document.form.message.value.length<10)
{
Alert ("Input text is less than 10!");
Document.form.MESSAGE.focus ();
return false;
}
return true;
}
-->
</script>
5 Chinese/English/digital/email address legality judgment
Copy Code code as follows:
<script language= "JavaScript" >
<!--
function Isenglish (name)//English value detection
{
if (name.length = 0)
return false;
for (i = 0; i < name.length; i++) {
if (Name.charcodeat (i) > 128)
return false;
}
return true;
}
function Ischinese (name)//Chinese value detection
{
if (name.length = 0)
return false;
for (i = 0; i < name.length; i++) {
if (Name.charcodeat (i) > 128)
return true;
}
return false;
}
function IsMail (name)/e-mail value detection
{
if (! Isenglish (name))
return false;
i = Name.indexof ("at");
j = Name Dot LastIndexOf ("at");
if (i = = 1)
return false;
if (i!= j)
return false;
if (i = = Name dot length)
return false;
return true;
}
function Isnumber (name)//numeric detection
{
if (name.length = 0)
return false;
for (i = 0; i < name.length; i++) {
if (Name.charat (i) < "0" | | name.charat (i) > "9")
return false;
}
return true;
}
function Checkform ()
{
if (! IsMail (Form). Email.value)) {
Alert ("Your email is illegal!) ");
Form. Email.focus ();
return false;
}
if (! isenglish (Form.name.value)) {
Alert ("The English name is illegal!") ");
Form.name.focus ();
return false;
}
if (! Ischinese (Form.cnname.value)) {
Alert ("Chinese name is illegal!") ");
Form.cnname.focus ();
return false;
}
if (! isnumber (Form). Publiczipcode.value)) {
Alert ("ZIP code not valid!) ");
Form. Publiczipcode.focus ();
return false;
}
return true;
}
-->
</SCRIPT>
6 Qualifying A form item cannot enter characters
Copy Code code as follows:
<script language= "JavaScript" >
<!--
function contain (Str,charset)//string contains test functions
{
var i;
for (i=0;i<charset.length;i++)
if (Str.indexof (Charset.charat (i)) >=0)
return true;
return false;
}
function Checkform ()
{
if ((contain (document.form.NAME.value,%/(/) ><)) | | (Contain (document.form.MESSAGE.value, "%/(/) ><"))
{
Alert ("entered an illegal character");
Document.form.NAME.focus ();
return false;
}
return true;
}
-->
</script>
Third, other verification:
1. Check whether a string of strings is all composed of numbers
Copy Code code as follows:
<script language= "Javascript" ><!--
function Checknum (str) {return Str.match (//d/) ==null}
Alert (Checknum ("1232142141"))
Alert (Checknum ("123214214A1"))
--></script>
2. How to judge whether it is a character
Copy Code code as follows:
if (/[^/x00-/xff]/g.test (s)) alert ("contains Chinese characters");
else alert ("All characters");
3. How to judge whether to contain Chinese characters
Copy Code code as follows:
if (Escape (str). IndexOf ("%u")!=-1) alert ("contains Chinese characters");
else alert ("All characters");
4. Mailbox Format Verification
Copy Code code as follows:
Function Name: Chkemail
Function Introduction: Check whether for email address
Parameter description: The string to check
Return value: 0: not 1: Yes
function Chkemail (a)
{var i=a.length;
var temp = a.indexof (' @ ');
var tempd = A.indexof ('. ');
if (Temp > 1) {
if ((i-temp) > 3) {
if ((I-TEMPD) >0) {
return 1;
}
}
}
return 0;
}
5. Digital format Verification
Copy Code code as follows:
Function Name: Fucchecknum
Feature Description: Check for numbers
Parameter description: The number to check
Return value: 1 is a number, 0 is not a number
function Fucchecknum (NUM)
{
var i,j,strtemp;
strtemp= "0123456789";
if (num.length== 0)
return 0
for (i=0;i<num.length;i++)
{
J=strtemp.indexof (Num.charat (i));
if (j==-1)
{
Indicates that a character is not a number
return 0;
}
}
Description is a number
return 1;
}
6. Telephone Number format verification
Copy Code code as follows:
Function Name: Fucchecktel
Function Description: Check whether the phone number
Parameter description: The string to check
Return value: 1 is legal, 0 is illegal
function Fucchecktel (TEL)
{
var i,j,strtemp;
Strtemp= "0123456789-() #";
for (i=0;i<tel.length;i++)
{
J=strtemp.indexof (Tel.charat (i));
if (j==-1)
{
Indicates that there are characters that are not legal
return 0;
}
}
Description Legal
return 1;
}
7. A function to determine whether the input is Chinese
Copy Code code as follows:
function Ischinese (s) {
var ret=true;
for (Var i=0;i<s.length;i++)
Ret=ret && (S.charcodeat (i) >=10000);
return ret;
}
8. A comprehensive function to judge the legality of user input
Copy Code code as follows:
<script language= "JavaScript" >
Limit the number of digits of the input character to begin
M is user input, n is the number of digits to limit
function Issmall (m,n)
{
if ((m<n) && (m>0)
{
return (false);
}
Else
{return (true);}
}
9. Determine whether the password is entered in a consistent
Copy Code code as follows:
function Issame (STR1,STR2)
{
if (STR1==STR2)
{return (true);}
Else
{return (false);}
}
10. Determine if the user name is a digital letter down line
Copy Code code as follows:
function Notchinese (str) {
var reg=/[^a-za-z0-9_]/g
if (Reg.test (str)) {
return (false);
}else{
return (true); }
}
Universal check function for form text field
Function: Detects all input text that must be non-null, such as name, account number, email address, etc.
The checksum is now only for text fields, and if you want to target other domain objects in the form, you can change the criteria for judgment.
How to: Add title text to the text field you want to detect. The text is in the prompt message, you want to prompt the user with the Chinese name of the field. For example, to detect user names
HTML follows <input name= "txt_1" title= "name", and, of course, it's best to edit the domain with visual tools such as Dreamweaver or something.
If you want to detect numeric types of data, then the domain ID unified to SZ.
JavaScript to determine the date type is more cumbersome, so there is no date-type validation program. The master can be added.
Program to compare grass, just to provide a train of thought. Initiate ：）
Oh, yes, function call method:< form onsubmit= "return Dovalidate ()" >
Copy Code code as follows:
function Dovalidate ()
{
FM=DOCUMENT.FORMS[0]//Only detect a form, if multiple can change the condition of judgment
for (i=0;i<fm.length;i++)
{
Detection criteria, depending on the type can be modified
if (fm.tagName.toUpperCase () = = "INPUT" &&fm.type.touppercase () = = "TEXT" && (fm.title!= ""))
if (fm.value= "/blog/=")//
{
Str_warn1=fm.title+ "cannot be empty!";
alert (STR_WARN1);
Fm.focus ();
return false;
}
if (fm.id.toUpperCase () = = "SZ")//Digital Checksum
{
if (isNaN (Fm.value))
{str_warn2=fm.title+ "wrong format";
alert (STR_WARN2);
Fm.focus ();
return false;
}
}
}
return true;
}
12. Verify that Radio is selected
Copy Code code as follows:
<script language= "JavaScript" >
function Checkform (obj)
{
for (i=0;i<obj.oo.length;i++)
if (obj.oo[i].checked==true) return true;
Alert ("Please select")
return false;
}
</script>
<form id= "Form1" Name= "Form1" method= "Post" action= "" onsubmit= "return Checkform (This)" >
<input type= "Radio" Name= "oo" value= "RadioButton"/>
<input type= "Radio" Name= "oo" value= "RadioButton"/>
<input type= "Submit" name= "Submission" value= "submitted"/>
</form>
I hope this article will help you with your JavaScript based Web programming.
