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How can the last character typed be tested for in OnKeyPress event.

Posted on 2004-10-27
321 Views
Last Modified: 2013-12-03
I have a JavaScript function that is triggered by the OnKeyPress event of various fields.  The function takes two parameters, the ID of the field and the type of data (Soc Sec #, phone # or date) the field contains.  It then inserts hyphens or slashes in the appropriate places.  It works fine unless the user types in the hyphens and slashes themselves.  In this case the character is duplicated and the user has to back space them out. I would like to put a test in for these characters but when the OnKeyPress event is triggered the last character typed is not yet included in the value of the field.  If someone could tell me how to test for the last character typed I'd appreciate it.  My code is below.

function setFormat(Field, FieldType){
var obj = document.getElementById(Field);
var len = obj.value.length;
      switch (FieldType){
            case 'SSNO':
                  if((len == 3||len == 6))
                        obj.value += '-';
                  else
                        return;
            case 'Date':
                  if(len == 2||len == 5)
                        obj.value += '/';
                  else
                        return;
            case 'PhoneNumber':
                  if(len == 3)
                        obj.value += '-';
                  else
                        return;
      }
}
0
Question by:leskelly
    8 Comments
     
    LVL 5

    Expert Comment

    by:jpontani
    Change the handler to the OnKeyUp event, that way it happens after the release the last key.  Also, it should check the last character to make sure it's not the hyphen or slash, then it will add it.

    function setFormat(Field, FieldType){
          var obj = document.getElementById(Field);
          var len = obj.value.length;
          switch (FieldType) {
                case 'SSNO':
                      if((len == 3||len == 6) && obj.value.charAt(len-1) != "-")
                            obj.value += '-';
                      else
                            return;
                case 'Date':
                      if((len == 2||len == 5) && obj.value.charAt(len-1) != "/")
                            obj.value += '/';
                      else
                            return;
                case 'PhoneNumber':
                      if((len == 3) && obj.value.charAt(len-1) != "-")
                            obj.value += '-';
                      else
                            return;
        }
    }
    0
     
    LVL 31

    Expert Comment

    by:GwynforWeb
    this should be called off onkeypress not onkeyup, the technique I have shown stops the user backspacing to add a \ or -

    <script>
    function setFormat(Field, FieldType){
    var obj = document.getElementById(Field);
    var len = obj.value.length;
         obj.value=  obj.value.replace(/\D/g,'')
         switch (FieldType){
              case 'SSNO':obj.value=obj.value.replace(/^(\d{3})/,'$1-')
                          obj.value=obj.value.replace(/^(\d{3}-\d{3})(\d+)/,'$1-$2')
                          return
              case 'Date':obj.value=obj.value.replace(/^(\d{2})/,'$1\/')
                          obj.value=obj.value.replace(/^(\d{2}\/\d{3})(\d+)/,'$1\/$2')
                          return
              case 'PhoneNumber':obj.value=obj.value.replace(/^(\d{3})/,'$1-')
                                 return
         }
    }
    </script>
    <body>

    <p><input type="text" id="snum1" name="SSNO"  onkeyup="setFormat('snum1','SSNO')">ssno<p>

    <input type="text" id="date1" name="Date" onkeyup="setFormat('date1','Date')">date <p>

    <p><input type="text" id="num1" name="PhoneNumber" onkeyup="setFormat('num1','PhoneNumber')">phone
    </body>

    0
     

    Author Comment

    by:leskelly
    I'm afraid I didn't make myself clear.  I'm not trying to prevent the user from backspacing to add a / or -.  What I want to do is test for those characters so that, if a user types them in because they don't realize they will be added for them, they will be ignored.
    0
     
    LVL 31

    Expert Comment

    by:GwynforWeb
    try my code it is the a standard way of doing these problems, I think you will find it meets you needs
    0
     

    Author Comment

    by:leskelly
    GwynforWeb,

    I tried your code and it worked except, for Social Security Numbers it is placing the second '-' one character further to the right then it should.  For dates it's the same thing the second '/' is one further to the right.  I'm sure it just takes a minor change to correct this but, as is obvious I don't know much about JavaScript.

    Les
    0
     
    LVL 31

    Expert Comment

    by:GwynforWeb
    is this it?

    <script>
    function setFormat(Field, FieldType){
    var obj = document.getElementById(Field);
    var len = obj.value.length;
         obj.value=  obj.value.replace(/\D/g,'')
         switch (FieldType){
              case 'SSNO':obj.value=obj.value.replace(/^(\d{3})/,'$1-')
                          obj.value=obj.value.replace(/^(\d{3}-\d{3})(\d+)/,'$1-$2')
                          return
              case 'Date':obj.value=obj.value.replace(/^(\d{2})/,'$1\/')
                          obj.value=obj.value.replace(/^(\d{2}\/\d{2})(\d+)/,'$1\/$2')
                          return
              case 'PhoneNumber':obj.value=obj.value.replace(/^(\d{2})/,'$1-')
                       return
         }
    }
    </script>

    <body>
    <p><input type="text" id="snum1" name="SSNO" onkeyup="setFormat('snum1','SSNO')">ssno</p>

    <p><input type="text" id="date1" name="Date" onkeyup="setFormat('date1','Date')">date</p>

    <p><input type="text" id="num1" name="PhoneNumber"  onkeyup="setFormat('num1','PhoneNumber')">phone </p>
    </body>
    0
     
    LVL 31

    Accepted Solution

    by:
    sorry I changed the wrong ones

    <script>
    function setFormat(Field, FieldType){
    var obj = document.getElementById(Field);
    var len = obj.value.length;
         obj.value=  obj.value.replace(/\D/g,'')
         switch (FieldType){
              case 'SSNO':obj.value=obj.value.replace(/^(\d{3})/,'$1-')
                          obj.value=obj.value.replace(/^(\d{3}-\d{2})(\d+)/,'$1-$2')
                          return
              case 'Date':obj.value=obj.value.replace(/^(\d{2})/,'$1\/')
                          obj.value=obj.value.replace(/^(\d{2}\/\d{2})(\d+)/,'$1\/$2')
                          return
              case 'PhoneNumber':obj.value=obj.value.replace(/^(\d{3})/,'$1-')
                       return
         }
    }
    </script>

    <body>
    <p><input type="text" id="snum1" name="SSNO" onkeyup="setFormat('snum1','SSNO')">ssno</p>

    <p><input type="text" id="date1" name="Date" onkeyup="setFormat('date1','Date')">date</p>

    <p><input type="text" id="num1" name="PhoneNumber" onkeyup="setFormat('num1','PhoneNumber')">phone
    </body>
    0
     

    Author Comment

    by:leskelly
    GwynforWeb

    That did the trick.  Thanks for your assistance.

    Les
    0

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