Check numbers entered

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  • Steve Wylie
    #1

    Check numbers entered

    I am constructing an HTML questionnaire and one of the questions
    requires people to rate some choices from 1 to 5, where 1 is their
    favourite and 5 is their least favourite:

    Car
    Bus
    Taxi cab
    Train
    Airplane

    Each choice has an INPUT TYPE=TEXT tag to contain the response. I
    also have a function that is called ONCHANGE in order to check that a
    number is entered between 1 and 5:

    function CheckNos(obj) {
    if(obj.value.ma tch(/[^\d]/) || obj.value<1 || obj.value>5)
    {alert("Please enter a number between 1 and 5");obj.value=" ";return
    false}
    }

    This works fine, but ideally I would like a function that could check
    ONCHANGE that someone has not filled in the same number twice, for
    example answered "1" for all of them. They are only allowed to use
    each rating number once, so rating their choice 1 to 5.

    Can anyone suggest a short function that could accomplish this easily?
    Could I use some kind of array with 5 elements and allocate a flag
    value once that number had been chosen, then check that the value had
    been set?

    I don't have a large amount of experience in Javascript so perhaps
    someone could help me.

    Thanks

    Steve Wylie
    United Kingdom
    Tags: None
    • Lee
      #2
      Re: Check numbers entered

      Steve Wylie said:[color=blue]
      >
      >I am constructing an HTML questionnaire and one of the questions
      >requires people to rate some choices from 1 to 5, where 1 is their
      >favourite and 5 is their least favourite:
      >
      >Car
      >Bus
      >Taxi cab
      >Train
      >Airplane
      >
      >Each choice has an INPUT TYPE=TEXT tag to contain the response. I
      >also have a function that is called ONCHANGE in order to check that a
      >number is entered between 1 and 5:
      >
      >function CheckNos(obj) {
      >if(obj.value.m atch(/[^\d]/) || obj.value<1 || obj.value>5)
      >{alert("Plea se enter a number between 1 and 5");obj.value=" ";return
      >false}
      >}
      >
      >This works fine, but ideally I would like a function that could check
      >ONCHANGE that someone has not filled in the same number twice, for
      >example answered "1" for all of them. They are only allowed to use
      >each rating number once, so rating their choice 1 to 5.
      >
      >Can anyone suggest a short function that could accomplish this easily?
      > Could I use some kind of array with 5 elements and allocate a flag
      >value once that number had been chosen, then check that the value had
      >been set?[/color]

      I'll assume that this is not a class assignment.

      Since the elements of the form are accessible as an array, you don't
      need to create a new one. If each entry is checked as it is changed,
      the only possible source of duplication is for this new value to be
      a duplicate of one existing value. All you need to do is to check
      each other member of this ranking group against this new value.

      Here's a simple (not completely idiot-proof or the most efficient)
      solution that's flexible enough to use more than once in the same
      form with a different number of members in each ranking group:

      <html>
      <head>
      <script type="text/javascript">
      function checkRank(box,f irstName,count) {

      // *box* is the text field whose onChange handler called us.
      // *firstName* is the name of the first field in this rank group.
      // *count* is the number of items being ranked.
      // Note that *count* must be less than 10.
      //
      // Check that text field *box* has a value from 1 to *count*,
      // then check *count* text fields beginning at *firstName*,
      // ensuring that no other field has the same value as *box*.


      var errMsg="Please enter a digit 1-"+count+"\n "
      +"that has not been used previously."

      box.value=box.v alue.replace(/\s*/g,""); // remove spaces

      if(!box.value.s earch(/^$/)) return; // this change is a deletion

      if(box.value.se arch(new RegExp("^[1-"+count+"]$"))){
      alert(errMsg);
      box.value="";
      return;
      }

      var group=box.form. elements;

      for(var i=0;i<group.len gth;i++){
      if(group[i].name==firstNam e){
      firstIndex=i;
      break;
      }
      }
      var firstIndex=i; // will be group.length if no match

      if(firstIndex+c ount-1>group.length) {
      alert("Bad arguments! Fire the web designer!");
      return;
      }

      for(var i=0;i<count;i++ ){
      if(group[firstIndex+i]!=box &&
      group[firstIndex+i].value==box.val ue){
      alert(errMsg);
      box.value="";
      return;
      }
      }

      }
      </script>
      </head>
      <body>
      <form>

      <table>
      <tr>
      <td align="right">C ar</td>
      <td><input name="car" size="3" onchange="check Rank(this,'car' ,5)"></td>
      </tr>
      <tr>
      <td align="right">B us</td>
      <td><input name="bus" size="3" onchange="check Rank(this,'car' ,5)"></td>
      </tr>
      <tr>
      <td align="right">T axi cab</td>
      <td><input name="taxi" size="3" onchange="check Rank(this,'car' ,5)"></td>
      </tr>
      <tr>
      <td align="right">T rain</td>
      <td><input name="train" size="3" onchange="check Rank(this,'car' ,5)"></td>
      </tr>
      <tr>
      <td align="right">A irplane</td>
      <td><input name="plane" size="3" onchange="check Rank(this,'car' ,5)"></td>
      </tr>
      </table>
      <input type="reset" value="clear">
      </form>
      </body>
      </html>



      <html>
      <head>
      <script type="text/javascript">
      function checkRank(box,f irstName,count) {

      // *box* is the text field whose onChange handler called us.
      // *firstName* is the name of the first field in this rank group.
      // *count* is the number of items being ranked.
      // Note that *count* must be less than 10.
      //
      // Check that text field *box* has a value from 1 to *count*,
      // then check *count* text fields beginning at *firstName*,
      // ensuring that none has the same value as *box*.

      var errMsg="Please enter a digit 1-"+count+"\n "
      +"that has not been used previously."

      box.value=box.v alue.replace(/\s*/g,""); // remove spaces

      if(!box.value.s earch(/^$/)) return; // change is a deletion

      if(box.value.se arch(new RegExp("^[1-"+count+"]$"))){
      alert(errMsg);
      box.value="";
      return;
      }

      group=box.form. elements;

      for(var i=0;i<group.len gth;i++){
      if(group[i].name==firstNam e){
      firstIndex=i;
      break;
      }
      }
      var firstIndex=i; // will be group.length if no match

      if(firstIndex+c ount-1>group.length) {
      alert("Bad arguments! Fire the web designer!");
      return;
      }

      for(var i=0;i<count;i++ ){
      if(group[firstIndex+i]!=box &&
      group[firstIndex+i].value==box.val ue){
      alert(errMsg);
      box.value="";
      return;
      }
      }

      }
      </script>
      </head>
      <body>
      <form>

      <table>
      <tr>
      <td align="right">C ar</td>
      <td><input name="car" size="3" onchange="check Rank(this,'car' ,5)"></td>
      </tr>
      <tr>
      <td align="right">B us</td>
      <td><input name="bus" size="3" onchange="check Rank(this,'car' ,5)"></td>
      </tr>
      <tr>
      <td align="right">T axi cab</td>
      <td><input name="taxi" size="3" onchange="check Rank(this,'car' ,5)"></td>
      </tr>
      <tr>
      <td align="right">T rain</td>
      <td><input name="train" size="3" onchange="check Rank(this,'car' ,5)"></td>
      </tr>
      <tr>
      <td align="right">A irplane</td>
      <td><input name="plane" size="3" onchange="check Rank(this,'car' ,5)"></td>
      </tr>
      </table>
      <input type="reset" value="clear">
      </form>
      </body>
      </html>

        Comment

        • Steve Wylie
          #3
          Re: Check numbers entered

          Hi Lee

          Thanks for replying with your suggested script. It actually kills 3 birds
          with one stone as I notice it also checks that the entry is a valid number
          and also that it is within the specified range, so that eliminates the need
          for me to use my existing function just to do that on its own.

          I'll have to wait till I get back to work on Thursday to try it out on my
          actual questionnaire.

          No, it's not a school assignment(!) I work for a local government authority
          in south-east England and your script will be used in the client-side
          validation of one of our consultation questionnaires we put out, asking
          residents in our district their views on crime, licensing laws and fire
          safety. So all pretty worthwhile stuff I think you'll agree. Think I'll
          put a comment line at the top of your function, "This script by Lee", not
          that anyone will see it unless they look at the source!

          Thanks again for your assistance.

          Steve Wylie


            Comment

            • Dr John Stockton
              #4
              Re: Check numbers entered

              JRS: In article <f2fafe4c.04062 20417.2930884a@ posting.google. com>, seen
              in news:comp.lang. javascript, Steve Wylie <stevewy@hotmai l.com> posted
              at Tue, 22 Jun 2004 05:17:45 :[color=blue]
              >I am constructing an HTML questionnaire and one of the questions
              >requires people to rate some choices from 1 to 5, where 1 is their
              >favourite and 5 is their least favourite:[/color]
              [color=blue]
              >Each choice has an INPUT TYPE=TEXT tag to contain the response. I
              >also have a function that is called ONCHANGE in order to check that a
              >number is entered between 1 and 5:
              >
              >
              >function CheckNos(obj) {
              >if(obj.value.m atch(/[^\d]/) || obj.value<1 || obj.value>5)
              >{alert("Plea se enter a number between 1 and 5");obj.value=" ";return
              >false}
              >}[/color]

              Between 1 & 5, the only integers are the digits 2 3 4.

              function CheckNos(obj) {
              if (!obj.value.mat ch(/^[1-5]$/)) {
              alert("Please enter a digit in 1 to 5") ;
              obj.value="" ;
              return false }
              return true }

              function CheckNos(obj) {
              var OK = (obj.value.matc h(/^[1-5]$/))
              if (!OK) {alert("Please enter a digit in 1 to 5") ; obj.value="" }
              return OK }
              [color=blue]
              >This works fine, but ideally I would like a function that could check
              >ONCHANGE that someone has not filled in the same number twice, for
              >example answered "1" for all of them. They are only allowed to use
              >each rating number once, so rating their choice 1 to 5.
              >
              >Can anyone suggest a short function that could accomplish this easily?
              > Could I use some kind of array with 5 elements and allocate a flag
              >value once that number had been chosen, then check that the value had
              >been set?[/color]

              Better to check on finished, since it is legitimate to put 1 2 3 1 5
              then change the first one to a 4.

              If you check the product for being 120, I think only 2 2 2 3 5 permuted
              will falsely pass. If you check also that the sum is 15 ... .

              Number them 1 2 3 5 7, check with /^[12357]$/, and you need a product of
              210, which no other combination of 1 2 3 5 7 can give.

              The following should work, more generally :
              var A = [] // an empty array
              for each entry, get value V, then A[V] = 1
              check that A[1]..A[5] all exist.
              or
              var A = []
              for each entry, get value V, then A[V] = '#'
              OK = A.join('').leng th==5

              --
              © John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 IE 4 ©
              <URL:http://jibbering.com/faq/> JL / RC : FAQ for news:comp.lang. javascript
              <URL:http://www.merlyn.demo n.co.uk/js-index.htm> jscr maths, dates, sources.
              <URL:http://www.merlyn.demo n.co.uk/> TP/BP/Delphi/jscr/&c, FAQ items, links.

                Comment

                • Steve Wylie
                  #5
                  Re: Check numbers entered

                  Thank you for your response, Dr John, but I think I'll stick with
                  Lee's suggestion because I can't understand your number play!
                  (Grade 4 CSE Maths, mate - this isn't my forté!)

                  Thanks anyway.

                  Steve

                    Comment

                    • Dr John Stockton
                      #6
                      Re: Check numbers entered

                      JRS: In article <f2fafe4c.04062 40145.65aeadc8@ posting.google. com>, seen
                      in news:comp.lang. javascript, Steve Wylie <stevewy@hotmai l.com> posted
                      at Thu, 24 Jun 2004 02:45:10 :[color=blue]
                      >Thank you for your response, Dr John, but I think I'll stick with
                      >Lee's suggestion because I can't understand your number play!
                      >(Grade 4 CSE Maths, mate - this isn't my forté!)[/color]

                      The paragraphs containing the numbers 120 & 210 only require what in my
                      time was taught to eight-year-olds; I don't know what CSE requirements
                      are.

                      For a set of numbers in 1..5 to multiply to 120 they must contain one 5,
                      and the others must make 24. To make 24, there must be a 3, and the
                      others must make 8. 8 can only be made as 4*2*1 and 2*2*2.

                      To get 210 by multiplying five numbers selected from 1 2 3 5 & 7, there
                      must be a 7, a 5, a 3, a 2 and a 1 (7 5 3 2 have no common factors).

                      The following paragraphs of that article show what should be the
                      shortest and most efficient check for the general case; but of course
                      they are a component rather than a fully-built answer.

                      --
                      © John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 IE 4 ©
                      <URL:http://jibbering.com/faq/> JL / RC : FAQ for news:comp.lang. javascript
                      <URL:http://www.merlyn.demo n.co.uk/js-index.htm> jscr maths, dates, sources.
                      <URL:http://www.merlyn.demo n.co.uk/> TP/BP/Delphi/jscr/&c, FAQ items, links.

                        Comment

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