Hướng dẫn javascript keypress decimal only

I want to enter a decimal point in a text box. I want to restrict the user by not allowing more than 1 digits after the decimal point.And restrict after decimal point enter only the number 5. I have written the code for it in the Keypress event. Using keypress event i want the series like:

1,1.5,2,2.5,3,3.5,4,4.5,5.

only the number between 1 and 5. how can i do this?

Check carat position to allow character insertion before the decimal. correct issue pointed out by ddlab's comment and only allow one dot.. The code is working but i have an issue if i enter 10 its working, i am not able to do so.i want numbers between 1 and 5.

function checkDecimal[_this, EventKey] {
    //            var key = EventKey.which || EventKey.keyCode;
    //            if [[key = 48 && _this.value.length == 0] || key == 8 || key == 9 || key == 37 || key == 39] {
    //                return true;
    //            }
    //            else {
    //                return false;
    //}


    var charCode = [EventKey.which] ? EventKey.which : event.keyCode;
    var number = _this.value.split['.'];


    if [charCode != 46 && charCode > 31 && [charCode < 49 || charCode > 53]] {
        return false;
    }

    //just one dot [thanks ddlab]
    if [number.length > 1 && charCode == 46] {
        return false;
    }
    //get the carat position
    var caratPos = getSelectionStart[_this];
    var dotPos = _this.value.indexOf["."];
    if [caratPos > dotPos && dotPos > -1 && [number[1].length > 0]] {

        return false;
    }
    return true;
}

function getSelectionStart[o] {
    if [o.createTextRange] {
        var r = document.selection.createRange[].duplicate[]
        r.moveEnd['character', o.value.length]
        if [r.text == ''] return o.value.length
        return o.value.lastIndexOf[r.text]
    } else return o.selectionStart
}
        its not working properly,Can you tell me what could be the issue?

i want to enter one digit before and after dot.not allow characters only integers

Hi all,

on one textbox i only want to enter numbers and decimal points. what i need is there should be only numbers , only one decimal points , back space allowd. no other special chars,no alphabets.

Can someone have any example.

function isNumberKey[evt] {
            var charCode = [evt.which] ? evt.which : event.keyCode
            if [charCode > 31 && [charCode < 48 || charCode > 57]]
                return false;

            return true;
        }

i tried this on keypress on textbox but this allows only numbers not decimal poitns

Try this

    
    

        function isNumberKey[evt, obj] {

            var charCode = [evt.which] ? evt.which : event.keyCode
            var value = obj.value;
            var dotcontains = value.indexOf["."] != -1;
            if [dotcontains]
                if [charCode == 46] return false;
            if [charCode == 46] return true;
            if [charCode > 31 && [charCode  57]]
                return false;
            return true;
        }



    


    
    
    

    
function checkDec[el]{
 var ex = /^[0-9]+\.?[0-9]*$/;
 if[ex.test[el.value]==false]{
   el.value = el.value.substring[0,el.value.length - 1];
  }
}
     
 

Updated 24-Feb-14 19:56pm

function validCheck[e] {
            var keyCode = [e.which] ? e.which : e.keyCode;
            if [[keyCode >= 48 && keyCode  31 && [keycode < 48 || keycode > 57] && keycode != 46] {
 alert[" You can enter only characters 0 to 9 "];

return false;
 }
 else return true;
 } 
 function isNumber[evt] {
 evt = [evt] ? evt : window.event;
 var charCode = [evt.which] ? evt.which : evt.keyCode;
 if [charCode > 31 && [charCode < 46 || charCode > 57 ] ] {
 return false;
 }
 return true;
 }
Updated
25-Feb-19 18:19pm 

  

 function isNumberDecimal[evt, element] {
 debugger;
 var charCode = [evt.which] ? evt.which : event.keyCode
 if [
 [charCode != 46 || $[element].val[].indexOf['.'] != -1] && 
 [charCode < 48 || charCode > 57]]
 return false;
 return true;
 } 
This content, along with any associated source code and files, is licensed under The Code Project Open License [CPOL]