How to allow only integers in a textbox

Question

In my form I want to allow typing of integer values only in a textbox  How to do that

User · Answer

step by step

given you have a textbox as following,

<asp:TextBox ID="TextBox13" runat="server" 
  onkeypress="return functionx(event)" >
</asp:TextBox>

you create a JavaScript function like this:

     <script type = "text/javascript">
         function functionx(evt) 
         {
            if (evt.charCode > 31 && (evt.charCode < 48 || evt.charCode > 57))
                  {
                    alert("Allow Only Numbers");
                    return false;
                  }
          }
     </script>

the first part of the if-statement excludes the ASCII control chars, the or statements exclued anything, that is not a number

User · Answer

You can use client-side validation    lt asp textbox onkeydown  return    event keyCode gt  65   amp  amp  event keyCode  32      gt

User · Answer

Try this   Note This is using Ajax Toolkit  First add Ajax Script Manager and use the below Code   lt asp FilteredTextBoxExtender ID  TextBox1 FilteredTextBoxExtender  runat  server  Enabled  True  TargetControlID  TextBox1  FilterType  Numbers  gt   lt  asp FilteredTextBoxExtender gt

User · Answer

try this instead  Note This is using Ajax Toolkit  First add Ajax Script Manager and use the below Code to apply filter to the textbox  Provide the Namespace at the beginning of the asp net page   lt    Register Assembly  AjaxControlToolkit  Namespace  AjaxControlToolkit  TagPrefix  cc1    gt    lt asp TextBox ID  TxtBox  runat  server  gt  lt  asp TextBox gt   lt cc1 FilteredTextBoxExtender ID  FilteredTextBoxExtender1  runat  server  Enabled  True  TargetControlID  TxtBox  FilterType  Numbers  FilterMode  ValidChars  gt   lt  cc1 FilteredTextBoxExtender gt

User · Answer

I would use ASP NET Ajax Filter TextBoxExtender control  https   www aspsnippets com Articles ASPNet-AJAX-FilteredTextBoxExtender-Control-Example aspx

User · Answer

we can use javascript code  function validateAlphaNumericCode event        keyEntry    event which    event which   event keyCode      if    keyEntry  gt    65    amp  amp   keyEntry  lt    90         keyEntry  gt    97    amp  amp   keyEntry  lt    122        keyEntry     37       keyEntry     39       keyEntry     46       keyEntry     8       keyEntry     9       keyEntry     95        keyEntry  gt    48    amp  amp   keyEntry  lt    57             return true      else         return false      validate this code with your textbox

User · Answer

lt HTML gt      lt HEAD gt      lt SCRIPT language Javascript gt        function isNumberKey evt                   var charCode    evt which    evt which   evt keyCode           if  charCode  gt  31  amp  amp   charCode  lt  48    charCode  gt  57               return false               return true              lt  SCRIPT gt      lt  HEAD gt      lt BODY gt         lt INPUT id  txtChar  onkeypress  return isNumberKey event   type  text  name  txtChar  gt      lt  BODY gt   lt  HTML gt

User · Answer

An even easier method is to use the TextMode attribute    lt asp TextBox runat  server  ID  txtTextBox  TextMode  Number  gt

User · Answer

Easy Method -  You can use the onkeydown Property of the TextBox for limiting its value to numbers only    Very easy   -    lt asp TextBox ID  TextBox1  runat  server  onkeydown    return    event keyCode gt  65   amp  amp  event keyCode  32    gt  lt  asp TextBox gt      keyCode  65  check is for excludng the Albphabets    keyCode  32 check is for excluding the Space character inbetween the numbers

User · Answer

You can use RegularExpressionValidator for this  below is the sample code    lt asp TextBox ID  TextBox1  runat  server  gt  lt  asp TextBox gt   lt asp RegularExpressionValidator ID  RegularExpressionValidator1      ControlToValidate  TextBox1  runat  server      ErrorMessage  Only Numbers allowed      ValidationExpression   d   gt   lt  asp RegularExpressionValidator gt    above TextBox only allowed integer to be entered because in RegularExpressionValidator has field called ValidationExpression  which validate the TextBox  However  you can modify as per your requirement   You can see more example in MVC and Jquery here

User · Answer

You can use RegularExpressionValidator    lt asp TextBox ID  viewTextBox  runat  server  Text  0  gt  lt  asp TextBox gt   lt asp RegularExpressionValidator ID  viewRegularExpressionValidator  runat  server  ValidationExpression   0-9  1 50   ControlToValidate  viewTextBox  ErrorMessage  Please Enter numbers only  gt   lt  asp RegularExpressionValidator gt

User · Answer

User below regular expression validator              lt asp RegularExpressionValidator ID  RegularExpressionValidatorNumeric  runat  server  ControlToValidate  yourControl ID  ErrorMessage  Registraion ID Should be a Numeric  ValidationExpression    d      gt  lt  asp RegularExpressionValidator gt

User · Answer

You might find useful microsoft msdn article How To  Use Regular Expressions to Constrain Input in ASP NET  Take a look at  Common Regular Expressions  Table  It has validation example for  Non- negative integer    d     This expression validates that the field contains an integer greater than zero

User · Answer

if  document de your textbox id value                        var checkOK    0123456789      var checkStr   document de your textbox id value             var allValid   true     for  i   0   i  lt  checkStr length   i             ch   checkStr charAt i                  for  j   0   j  lt  checkOK length   j        if  ch    checkOK charAt j       break      if  j    checkOK length                 allValid   false         break                          if   allValid                          alert  Please enter only numeric characters in the text box            document de your textbox id focus

User · Answer

Try This       lt input type  text   onkeypress    return isDigit event this value     gt   function isDigit evt  txt            var charCode    evt which    evt which   event keyCode          var c   String fromCharCode charCode            if  txt indexOf c   gt  0  amp  amp  charCode    46                return false                    else if  charCode    46  amp  amp  charCode  gt  31  amp  amp   charCode  lt  48    charCode  gt  57                 return false                     return true          Call this function from input textbox on onkeypress event

User · Answer

function CheckNumeric event        var  key    window Event    event which   event keyCode       if    key  gt  95  amp  amp   key  lt  106       key  gt  47  amp  amp   key  lt  58      key    8     key    9     key    37     key    39     key    190     key    110            return true            else           return false            lt input type  text  onkeydown  return CheckNumerick event      gt    Accept Keys  Numbers   NumPedNumbers   Tab               LeftButton   RightButton   Delete   BackSpace

User · Answer

It can be done with a compare validator as below  Unlike the other answers  this also allows negative numbers to be entered  which is valid for integer values    lt asp TextBox ID  TextBox1  runat  server  gt  lt  asp TextBox gt   lt asp CompareValidator ControlToValidate  TextBox1  runat  server  ErrorMessage  Integers only please  Operator  DataTypeCheck  Type  Integer   gt  lt  asp CompareValidator gt

User · Answer

Another solution is to use a RangeValidator where you set Type  Integer  like this    lt asp RangeValidator runat  server      id  valrNumberOfPreviousOwners      ControlToValidate  txtNumberOfPreviousOwners      Type  Integer      MinimumValue  0      MaximumValue  999      CssClass  input-error      ErrorMessage  Please enter a positive integer       Display  Dynamic  gt   lt  asp RangeValidator gt    You can set reasonable values for the MinimumValue and MaximumValue attributes too

User · Answer

Just use   lt input type  number  id  foo  runat  server    gt    It ll work on all modern browsers except IE  10  Here is a full list   http   caniuse com  feat input-number

[asp.net] How to allow only integers in a textbox?

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