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Javascript can only enter regular expressions such as numbers, numbers, and letters.

Source: Internet
Author: User
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1. Only numeric code can be entered in the text box (decimal point cannot be entered)
<Input onkeyup = "this. value = This. value. replace (/\ D/g, '')" onafterpaste = "this. value = This. value. replace (/\ D/g, '')">

2. Only numbers can be entered, and decimal points can be entered.
<Input onkeyup = "If (isnan (value) Execcommand ('undo ')" onafterpaste = "If (isnan (value) Execcommand ('undo')">
<Input name = txt1 onchange = "If (/\ D /. test (this. value) {alert ('only numbers allowed '); this. value = '';}">

3. Number and decimal point method 2
<Input type = text t_value = "" o_value = "" onkeypress = "If (! This. value. Match (/^ [\ + \-]? \ D *? \.? \ D *? $/) This. value = This. t_value; else this. t_value = This. value; If (this. value. Match (/^ (? : [\ + \-]? \ D + (? : \. \ D + )?)? $/) This. o_value = This. Value "onkeyup =" If (! This. value. Match (/^ [\ + \-]? \ D *? \.? \ D *? $/) This. value = This. t_value; else
This. t_value = This. value; If (this. value. Match (/^ (? : [\ + \-]? \ D + (? : \. \ D + )?)? $/) This. o_value = This. Value "onblur =" If (! This. value. Match (/^ (? : [\ + \-]? \ D + (? : \. \ D + )? | \. \ D *?)? $/) This. value = This. o_value; else {If (this. value. match (/^ \. \ D + $/) This. value = 0 + this. value; If (this. value. match (/^ \. $/) This. value = 0; this. o_value = This. value} ">

4. Only letters and Chinese characters can be entered
<Input onkeyup = "value = value. replace (/[\ D]/g, '')" onbeforepaste = "clipboardData. setdata ('text', clipboardData. getdata ('text '). replace (/[\ D]/g, '')" maxlength = 10 name = "Numbers">

5. Only English letters and numbers are allowed. Chinese characters are not allowed.
<Input onkeyup = "value = value. Replace (/[^ \ W \. \/]/ig,'') ">

6. Only numbers and English letters can be entered. <font color = "red"> Chun </font>
<Input onkeyup = "value = value. Replace (/[^ \ d | Chun]/g,'') ">

7. After the decimal point, you can enter a maximum of two digits (numbers and Chinese characters). You cannot enter letters or operator numbers:
<Input onkeypress = "If (event. keycode <48 | event. keycode> 57) & event. keycode! = 46 |/\. \ D $/. Test (value) event. returnvalue = false ">

8. A maximum of two digits (numbers, letters, and Chinese characters) can be entered after the decimal point. You can enter the operator number:
<Input onkeyup = "this. value = This. value. replace (/^ (\-) * (\ D + )\. (\ D ). * $/, '$1 $2. $ 3') ">

It can only be a number, a decimal point, or a plus or minus sign.

Onkeypress = "Return event. keycode> = 4 & event. keycode <= 57"

 

========================================================== ========================================================== ==================================

JS allows only numbers in the input box
Description
1 can only input 0 to 9 and decimal point
2. Only numbers can be pasted.
3. content cannot be dragged in.
4 forbidden to use input methods

<HTML>
<Head>
<Meta http-equiv = "Content-Type" content = "text/html; charset = gb2312">
<Title> javascript can only enter numbers and decimal places </title>
<Script language = "JavaScript" type = "text/JavaScript">
Function clearnonum (OBJ)
{
// Replace all non-numeric values first, except numbers and.
OBJ. value = obj. value. Replace (/[^ \ D.]/g ,"");
// Ensure that the first digit is a number instead of a number.
OBJ. value = obj. value. Replace (/^ \./g ,"");
// Ensure that there is only one and no more.
OBJ. value = obj. value. Replace (/\. {2,}/g ,".");
// Ensure that the message appears only once, but not more than twice.
OBJ. value = obj. value. replace (". "," $ # $ "). replace (/\. /g ,""). replace ("$ # $ ",". ");
}
</SCRIPT>
</Head>
<Body>
<! -- Add the following code to the <body> and </body> -->
Only text boxes with numbers and decimal places can be entered: <input id = "input1" onkeyup = "clearnonum (this)">
</Body>
</Html>

 

<! Doctype HTML public "-// W3C // dtd html 4.01 transitional // en">
<HTML>
<Head>
<Title> only numbers can be entered in the input box </title>
</Head>

<Body>
<Input type = "text" name = "num" id = "num" onkeypress = "Return keypress (event)">
<SCRIPT type = "text/JavaScript">
Function keypress (e ){
EE = e? E: window. event? Event: NULL;
VaR keynum = event. keycode;
VaR keychar = string. fromcharcode (keynum );
VaR regdig =/\ D/g;
If (regdig. Test (keychar) | keychar = ""){
Return true;
}
VaR regdot =/\./g;
If (regdot. Test (keychar )&&! Regdot. Test (document. getelementbyid ("num"). Value )){
Return true;
}
Return false;
}
</SCRIPT>
</Body>
</Html>

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

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