server side validation vs. client side validation


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Thread: server side validation vs. client side validation

  1. #1
    s Guest

    server side validation vs. client side validation


    Hi all.
    I want to know that what the difference between server side validation and
    client side validation is?Can every one build a scenariofor them when sending
    data from a form to server? And also how can distinguish them?What is the
    syntaxes for them?
    TIA
    s

  2. #2
    Dan Guest

    Re: server side validation vs. client side validation


    Client side validation runs in the browser to check that the form values are
    of the correct type. JavaScript should always be used on the client side
    since it is supported by both Netscape and IE. (VBScript is supported only
    by IE).

    Server side validation checks the code that is submitted to make sure it
    is correct. Good applications will use both server and client validation.
    One reason for this is that it would be possible for someone else to write
    a form that calls your .asp page - they might not use client side validation
    and might throw in garbage data.

    Here is a brief example that uses client code to make sure that required
    fields have been entered. Normally client side code gets much more detailed
    because you want to check that a phone number looks like a phone number,
    an email address looks like an email address, etc. Any good book on JavaScript
    - like O'Reilly's JavaScript, The Definitive Guide - goes into the details.

    Also note that I didn't include any server validation code in this example.

    <%
    if request.form("task") = "Submit Form" then
    ' Form processing code goes here.
    response.write("This is the data you submitted:<br><br>")
    response.write(request.form("field1") & "<br>")
    response.write(request.form("field2") & "<br>")
    response.write(request.form("field3") & "<br>")
    response.write(request.form("field4") & "<br>")
    end if
    %>
    <html>
    <head>
    <title>Page Title</title>
    <script language="JavaScript" type="text/javascript">
    // fieldChecker checks to make sure that all required fields have been filled
    out.
    function fieldChecker(f) {
    for (var x=0;x<f.length - 2;x++) {
    if (f.elements[x].optional == null) {
    if (f.elements[x].value == '') {
    alert('This field is required.');
    f.elements[x].focus();
    return false;
    }
    }
    }
    return true;
    }
    </script>
    </head>
    <body>
    <form name="Sample" method="post" action="sample.asp" onSubmit="this.field3.optional=true;
    this.field4.optional=true; return fieldChecker(this);">
    <br>
    Field 1: (Required) <input type="text" name="field1"><br><br>
    Field 2: (Required) <input type="text" name="field2"><br><br>
    Field 3: <input type="text" name="field3"><br><br>
    Field 4: <input type="text" name="field4"><br><br>
    <input type="submit" name="task" value="Submit Form">
    </form>
    </body>
    </html>


    "s" <s_mahd@yahoo.com> wrote:
    >
    >Hi all.
    >I want to know that what the difference between server side validation

    and
    >client side validation is?Can every one build a scenariofor them when sending
    >data from a form to server? And also how can distinguish them?What is the
    >syntaxes for them?
    >TIA
    >s



  3. #3
    Russell Jones Guest

    Re: server side validation vs. client side validation

    As Dan said, you should always write server-side validation code even if you
    validate the data on the client. But the *reason* for writing client-side
    validation is to avoid the round-trip to the server that would otherwise be
    required to validate the data. In other words, if the user enters invalid
    data, it's much more efficient and user-friendly to trap the error *before*
    sending the data to the server, where--if the data is invalid--you'll have
    to rebuild the page and maintain the page state as well so that the user can
    fix the invalid value.


    "s" <s_mahd@yahoo.com> wrote in message news:3b8e2293$1@news.devx.com...
    >
    > Hi all.
    > I want to know that what the difference between server side validation

    and
    > client side validation is?Can every one build a scenariofor them when

    sending
    > data from a form to server? And also how can distinguish them?What is the
    > syntaxes for them?
    > TIA
    > s




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