my function needs a for loop.

Discussion in 'Javascript' started by Abby Lee, Sep 3, 2004.

  1. Abby Lee

    Abby Lee Guest

    My function works but there has got to be a way to make a for loop to
    handle this...but I can't get a for loop to work. You can tell, I'm
    not very good at this...help.

    "myvalue" is the number of miles the person enters
    "myitem" is the row...there are seven rows where they can list
    expenses.
    "myvalue" * .375 = amount to be reimbursed
    All the rows are added and placed into the total.


    function autoReimb(myvalue,myitem){
    var nrow = "autoReimb" + myitem;
    if(isPositiveInteger(myvalue.value)){
    var amount = myvalue.value * .375;
    formatedamt = format(amount)
    eval("document.forms[0]." + nrow + ".value = formatedamt");
    if(isPositiveInteger(document.forms[0].miles1.value))
    var reimb1 = document.forms[0].autoReimb1.value;
    else var reimb1 = 0;
    if(isPositiveInteger(document.forms[0].miles2.value))
    var reimb2 = document.forms[0].autoReimb2.value;
    else var reimb2 = 0;
    if(isPositiveInteger(document.forms[0].miles3.value))
    var reimb3 = document.forms[0].autoReimb3.value;
    else var reimb3 = 0;
    if(isPositiveInteger(document.forms[0].miles4.value))
    var reimb4 = document.forms[0].autoReimb4.value;
    else var reimb4 = 0;
    if(isPositiveInteger(document.forms[0].miles5.value))
    var reimb5 = document.forms[0].autoReimb5.value;
    else var reimb5 = 0;
    if(isPositiveInteger(document.forms[0].miles6.value))
    var reimb6 = document.forms[0].autoReimb6.value;
    else var reimb6 = 0;
    if(isPositiveInteger(document.forms[0].miles5.value))
    var reimb7 = document.forms[0].autoReimb7.value;
    else var reimb7 = 0;

    var totalauto = (reimb1 * 1) + (reimb2 * 1) + (reimb3 * 1) + (reimb4
    * 1) + (reimb5 * 1) + (reimb6 * 1) + (reimb7 * 1);
    document.forms[0].autotot.value = format(totalauto);
    }
    else eval("document.forms[0]." + nrow + ".value = ''");
    } //End Function
    Abby Lee, Sep 3, 2004
    #1
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  2. Abby Lee

    McKirahan Guest

    "Abby Lee" <> wrote in message
    news:...
    > My function works but there has got to be a way to make a for loop to
    > handle this...but I can't get a for loop to work. You can tell, I'm
    > not very good at this...help.
    >
    > "myvalue" is the number of miles the person enters
    > "myitem" is the row...there are seven rows where they can list
    > expenses.
    > "myvalue" * .375 = amount to be reimbursed
    > All the rows are added and placed into the total.
    >
    >
    > function autoReimb(myvalue,myitem){
    > var nrow = "autoReimb" + myitem;
    > if(isPositiveInteger(myvalue.value)){
    > var amount = myvalue.value * .375;
    > formatedamt = format(amount)
    > eval("document.forms[0]." + nrow + ".value = formatedamt");
    > if(isPositiveInteger(document.forms[0].miles1.value))
    > var reimb1 = document.forms[0].autoReimb1.value;
    > else var reimb1 = 0;
    > if(isPositiveInteger(document.forms[0].miles2.value))
    > var reimb2 = document.forms[0].autoReimb2.value;
    > else var reimb2 = 0;
    > if(isPositiveInteger(document.forms[0].miles3.value))
    > var reimb3 = document.forms[0].autoReimb3.value;
    > else var reimb3 = 0;
    > if(isPositiveInteger(document.forms[0].miles4.value))
    > var reimb4 = document.forms[0].autoReimb4.value;
    > else var reimb4 = 0;
    > if(isPositiveInteger(document.forms[0].miles5.value))
    > var reimb5 = document.forms[0].autoReimb5.value;
    > else var reimb5 = 0;
    > if(isPositiveInteger(document.forms[0].miles6.value))
    > var reimb6 = document.forms[0].autoReimb6.value;
    > else var reimb6 = 0;
    > if(isPositiveInteger(document.forms[0].miles5.value))
    > var reimb7 = document.forms[0].autoReimb7.value;
    > else var reimb7 = 0;
    >
    > var totalauto = (reimb1 * 1) + (reimb2 * 1) + (reimb3 * 1) + (reimb4
    > * 1) + (reimb5 * 1) + (reimb6 * 1) + (reimb7 * 1);
    > document.forms[0].autotot.value = format(totalauto);
    > }
    > else eval("document.forms[0]." + nrow + ".value = ''");
    > } //End Function



    1) Use "document.getElementById" not "eval()".

    2) You have "document.forms[0].miles5.value" twice;
    instead on "document.forms[0].miles7.value"

    3) You should use "myvalue" not "myvalue.value".

    4) It would have been easier to help you if you had included the <form>.

    5) It can be cleaned up a lot more but the following works; watch for
    word-wrap.

    <html>
    <head>
    <title>mileage.htm</title>
    <script type="text/javascript">
    /*
    * My function works but there has got to be a way to make a for loop to
    * handle this...but I can't get a for loop to work. You can tell, I'm
    * not very good at this...help.
    *
    * "myvalue" is the number of miles the person enters
    * "myitem" is the row...there are seven rows where they can list expenses.
    * "myvalue" * .375 = amount to be reimbursed
    * All the rows are added and placed into the total.
    *
    */

    function validate() {
    // autoReimb(20,2)
    for (var i=1; i<8; i++) {
    autoReimb(document.getElementById("miles"+i).value,i)
    }
    }

    function autoReimb(myvalue,myitem){
    var nrow = "autoReimb" + myitem;
    if(isPositiveInteger(myvalue)){
    var amount = myvalue * .375;
    formatedamt = format(amount)
    //eval("document.forms[0]." + nrow + ".value = formatedamt");
    document.getElementById(nrow).value = formatedamt;
    if(isPositiveInteger(document.forms[0].miles1.value))
    var reimb1 = document.forms[0].autoReimb1.value;
    else var reimb1 = 0;
    if(isPositiveInteger(document.forms[0].miles2.value))
    var reimb2 = document.forms[0].autoReimb2.value;
    else var reimb2 = 0;
    if(isPositiveInteger(document.forms[0].miles3.value))
    var reimb3 = document.forms[0].autoReimb3.value;
    else var reimb3 = 0;
    if(isPositiveInteger(document.forms[0].miles4.value))
    var reimb4 = document.forms[0].autoReimb4.value;
    else var reimb4 = 0;
    if(isPositiveInteger(document.forms[0].miles5.value))
    var reimb5 = document.forms[0].autoReimb5.value;
    else var reimb5 = 0;
    if(isPositiveInteger(document.forms[0].miles6.value))
    var reimb6 = document.forms[0].autoReimb6.value;
    else var reimb6 = 0;
    if(isPositiveInteger(document.forms[0].miles7.value))
    var reimb7 = document.forms[0].autoReimb7.value;
    else var reimb7 = 0;
    var totalauto = (reimb1 * 1) + (reimb2 * 1) + (reimb3 * 1) + (reimb4
    * 1) + (reimb5 * 1) + (reimb6 * 1) + (reimb7 * 1);
    document.forms[0].autotot.value = format(totalauto);
    }
    //else eval("document.forms[0]." + nrow + ".value = ''");
    else document.getElementById(nrow).value = "";
    }
    function format(amount) {
    // { your code }
    return amount;
    }
    function isPositiveInteger () {
    // { your code }
    return true;
    }
    </script>
    <style type="text/css">
    ..rite { text-align:right; width:40px }
    </style>
    </head>
    <body>
    <form>
    <br><input type="text" name="miles1" value="10" class="rite">
    = <input type="text" name="autoReimb1" value="" class="rite">
    <br><input type="text" name="miles2" value="20" class="rite">
    = <input type="text" name="autoReimb2" value="" class="rite">
    <br><input type="text" name="miles3" value="30" class="rite">
    = <input type="text" name="autoReimb3" value="" class="rite">
    <br><input type="text" name="miles4" value="40" class="rite">
    = <input type="text" name="autoReimb4" value="" class="rite">
    <br><input type="text" name="miles5" value="50" class="rite">
    = <input type="text" name="autoReimb5" value="" class="rite">
    <br><input type="text" name="miles6" value="60" class="rite">
    = <input type="text" name="autoReimb6" value="" class="rite">
    <br><input type="text" name="miles7" value="70" class="rite">
    = <input type="text" name="autoReimb7" value="" class="rite">
    <br><input type="text" name="autotot">
    <input type="button" value="Calc" onclick="validate()">
    </form>
    </body>
    </html>
    McKirahan, Sep 3, 2004
    #2
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  3. On Fri, 03 Sep 2004 20:54:49 GMT, McKirahan <> wrote:

    [snip]

    > 1) Use "document.getElementById" not "eval()".


    Why? Neither is the optimum solution (though gEBI is better).

    document.forms[0].elements['miles' + n].value

    gEBI requires a recent browser. The line above doesn't.

    [snip]

    > 3) You should use "myvalue" not "myvalue.value".


    It would appear that myvalue is a form control that contains a number. If
    it were an actual number, undefined would result from the property access.

    [snip]

    > 5) It can be cleaned up a lot more but the following works; watch for
    > word-wrap.


    Yes, it could.

    [snip]

    function isPosInt(v) {
    return /^0|([1-9]\d*)$/.test(v);
    }

    function autoReimb(val, itm) {
    var e = document.forms[0].elements,
    r = 'autoReimb' + itm,
    t = 0;

    if(isPosInt(val.value)) {
    e[r].value = format(val.value * 0.375);
    for(var i = 1; i <= 7; ++i) {
    if(isPosInt(e['miles' + i].value)) {
    t += +e['autoReimb' + i].value;
    }
    }
    e['autotot'].value = format(t);
    } else {
    e[r].value = '';
    }
    }

    To the OP:

    Untested, but it's what I believe it's you were after.

    Hope that helps,
    Mike

    --
    Michael Winter
    Replace ".invalid" with ".uk" to reply by e-mail.
    Michael Winter, Sep 4, 2004
    #3
  4. Abby Lee

    McKirahan Guest

    "Michael Winter" <> wrote in message
    news:eek:psdrxjdk4x13kvk@atlantis...
    > On Fri, 03 Sep 2004 20:54:49 GMT, McKirahan <> wrote:
    >
    > [snip]
    >
    > > 1) Use "document.getElementById" not "eval()".

    >
    > Why? Neither is the optimum solution (though gEBI is better).
    >
    > document.forms[0].elements['miles' + n].value
    >
    > gEBI requires a recent browser. The line above doesn't.


    http://www.jibbering.com/faq/#FAQ4_40

    > [snip]
    >
    > > 3) You should use "myvalue" not "myvalue.value".

    >
    > It would appear that myvalue is a form control that contains a number. If
    > it were an actual number, undefined would result from the property access.
    >


    "myvalue" is a input parameter to the function:

    function autoReimb(myvalue,myitem){

    > [snip]
    >
    > > 5) It can be cleaned up a lot more but the following works; watch for
    > > word-wrap.

    >
    > Yes, it could.
    >
    > [snip]
    >
    > function isPosInt(v) {
    > return /^0|([1-9]\d*)$/.test(v);
    > }
    >
    > function autoReimb(val, itm) {
    > var e = document.forms[0].elements,
    > r = 'autoReimb' + itm,
    > t = 0;
    >
    > if(isPosInt(val.value)) {
    > e[r].value = format(val.value * 0.375);
    > for(var i = 1; i <= 7; ++i) {
    > if(isPosInt(e['miles' + i].value)) {
    > t += +e['autoReimb' + i].value;
    > }
    > }
    > e['autotot'].value = format(t);
    > } else {
    > e[r].value = '';
    > }
    > }


    Good suggestion!

    >
    > To the OP:
    >
    > Untested, but it's what I believe it's you were after.
    >
    > Hope that helps,
    > Mike
    >
    > --
    > Michael Winter
    > Replace ".invalid" with ".uk" to reply by e-mail.
    McKirahan, Sep 4, 2004
    #4
  5. On Sat, 04 Sep 2004 02:25:40 GMT, McKirahan <> wrote:

    > "Michael Winter" <> wrote in message
    > news:eek:psdrxjdk4x13kvk@atlantis...


    [snip]

    >> document.forms[0].elements['miles' + n].value
    >>
    >> gEBI requires a recent browser. The line above doesn't.

    >
    > http://www.jibbering.com/faq/#FAQ4_40


    What's that meant to imply?

    [snip]

    >> It would appear that myvalue is a form control that contains a number.
    >> If it were an actual number, undefined would result from the property
    >> access.

    >
    > "myvalue" is a input parameter to the function:


    I know. However, the OP's original code suggests that it is a reference to
    a form element, not an actual value. If it were a value, myvalue.value
    would evaluate to undefined and I'm sure that if the OP made that mistake,
    it would have been explicitly mentioned ("Why does myvalue.value not give
    me the value I passed?") or corrected before posting to the group.

    If I'm wrong, then you were correct in your first post in that the OP
    should have shown the actual function call on the FORM element.

    [snip]

    Mike

    --
    Michael Winter
    Replace ".invalid" with ".uk" to reply by e-mail.
    Michael Winter, Sep 4, 2004
    #5
  6. Abby Lee

    McKirahan Guest

    "Michael Winter" <> wrote in message
    news:eek:psdsiucx5x13kvk@atlantis...
    > On Sat, 04 Sep 2004 02:25:40 GMT, McKirahan <> wrote:
    >
    > > "Michael Winter" <> wrote in message
    > > news:eek:psdrxjdk4x13kvk@atlantis...

    >
    > [snip]
    >
    > >> document.forms[0].elements['miles' + n].value
    > >>
    > >> gEBI requires a recent browser. The line above doesn't.

    > >
    > > http://www.jibbering.com/faq/#FAQ4_40

    >
    > What's that meant to imply?
    >
    > [snip]


    Anytime eval() usage is brought up in this ng it gets jumped on.

    Here's a recent post which discusses "Why is 'eval' evil?".

    From: Lasse Reichstein Nielsen ()
    Subject: Re: Why is 'eval' evil?
    View: Complete Thread (8 articles)
    Original Format
    Newsgroups: comp.lang.javascript
    Date: 2004-04-04 16:06:50 PST


    Reply Via Newsgroup <> writes:

    > I don't use eval alot in my scripts - but I do use it - and since I
    > always out to learn more / improve my javascript skills, I'm curious
    > why something I thought 'normal' would be considered abnormal.
    >
    > Can someone put some meat on the bones of 'eval' - its advantages (if
    > any) and its disadvantages (which seem great).


    As you might guess, it's not the first time someone has questionend
    the "eval is evil" slogan :) It even made the FAQ.
    <URL:http://jibbering.com/faq/#FAQ4_40>

    The short argument for not using eval is:
    "It's shooting pidgeons with cannons."
    Sure, it get's the job done, but it's harder to control and takes a
    lot more resources than needed, and when it fails, it fails
    spectacularly (read: blows up in your face).

    There is (almost) no situation where there isn't another method that
    also does the job, and both more efficiently and a lot safer.

    With "more efficient" I mean that it uses fewer resources. The "eval"
    function works by first turning its argument into a string, then it
    parses the string as a Javascript program and finally it evaluates
    it. This is a very expensive operation, and the generality of it is
    only needed in rare cases that most people writing web pages will
    never meet.

    With "safer" I mean that it it is less likely to fail spectacularly.
    Since eval can execute arbitrary Javascript expressions, passing the
    wrong argument can cause arbitrary errors. On a server, using eval on
    a user supplied string is a *very* bad idea. On a client, the main
    problem is that the error message is harder to connect to the actual
    error, and that, e.g., syntax errors in eval'ed code will only be
    detected at run time, not when the script is loaded. So: eval
    both introduces more possible errors and hides existing errors.

    The two most common (mis)uses of eval are:
    1) converting strings to numbers.
    There are plenty of dedicated functions and operators for just this
    problem: parseInt, parseFloat, Number, the prefix plus operator, most
    mathematical operators (string*1,string/1,string-0). Of these, the
    prefix plus is the fastest by a small margin. It is roughly *50* times
    faster than using eval (in my browser).

    2) accessing properties using a computed name.
    Example:
    eval("document.images.img"+n+".src")
    Again it is inefficient, here compared to using square-bracket
    notation for property access:
    document.images['img'+n].src
    It is also error prone. There is no syntax check, and if the variable
    "n" contains something you didn't expect, then the failure can be
    hard to find. If the property is called something that is not an
    identifier (typically "foo[]", used by PHP for form controls, or
    perhaps "foo1.1"), then the eval method fails completely.

    This is what I take as a sign that the author doesn't know the
    language very well. Often the reason for using eval like this is
    that they don't know about this way to do property access, which
    is a fundamental part of the language. Using eval like this is a
    crutch that allows them to stagger along, getting something to
    run, whereas knowing the language would let them run :)

    Then there is the third misuse (which the mentioned calendar program
    also sufferend from): throwing in an eval "just for good measure",
    even though someone who knows the language can see that it doesn't do
    anything. :)

    So, eval isn't evil, that's just a good slogan :)

    Eval is *very* slow and dangerously error prone!

    For *that* reason, it should be avoided in 99.999% of all cases. As
    for the remaining two, when you meet them, you'll hopefully know the
    language well enough to be able to recognize them.

    /L
    --
    Lasse Reichstein Nielsen -
    DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleDOM.html>
    'Faith without judgement merely degrades the spirit divine.'
    McKirahan, Sep 4, 2004
    #6
  7. On Sat, 04 Sep 2004 12:50:28 GMT, McKirahan <> wrote:

    > "Michael Winter" <> wrote in message
    > news:eek:psdsiucx5x13kvk@atlantis...
    >
    >> On Sat, 04 Sep 2004 02:25:40 GMT, McKirahan <> wrote:
    >>
    >>> http://www.jibbering.com/faq/#FAQ4_40

    >>
    >> What's that meant to imply?

    >
    > Anytime eval() usage is brought up in this ng it gets jumped on.


    Unless this is purely for the OP's benefit, and I misunderstood, you
    haven't grasped my point: I'm not recommending eval (where is an eval call
    in my code?), I'm saying that getElementById is not the correct approach.

    [snip]

    Mike

    --
    Michael Winter
    Replace ".invalid" with ".uk" to reply by e-mail.
    Michael Winter, Sep 4, 2004
    #7
  8. Abby Lee

    Abby Lee Guest

    You guys are my heros. Thank you.
    Abby Lee, Sep 7, 2004
    #8
  9. McKirahan wrote:

    > "Michael Winter" <> wrote [...]:
    >> On Fri, 03 Sep 2004 20:54:49 GMT, McKirahan <> wrote:
    >>
    >> [snip]
    >>
    >> > 1) Use "document.getElementById" not "eval()".

    >>
    >> Why? Neither is the optimum solution (though gEBI is better).
    >>
    >> document.forms[0].elements['miles' + n].value

    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    >> gEBI requires a recent browser. The line above doesn't.

    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    > http://www.jibbering.com/faq/#FAQ4_40


    You read, but you do not understand.


    PointedEars
    --
    The fat man walks alone at midnight.
    Thomas 'PointedEars' Lahn, Sep 11, 2004
    #9
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