[nfbcs] More help with javascript calculater

Taylor Arndt taylorarndt99 at gmail.com
Sat Nov 26 02:06:03 UTC 2016


I am still not  sure,  what to do as i now can't get a result at all
<!DOCTYPE html
        <head>
                <title>Accessible calculator</title>
<script>

function  function_calculate()
{
	
	 if value selected="ad")
	 {
	 result="parcefirst_number+second_number);
	
document.getElementById('txtresult').innerHTML = myResult;
 }
 function function_subtract()
 {
  var first_number=parseFloat(document.getElementById('Text1').value);
                                var
second_number=parseFloat(document.getElementById('Text2').value);
                                var myResult=(first_number-second_number);

document.getElementById('txtresult').innerHTML = myResult;
  }
function function_Multiply()
{}
  var first_number=parseFloat(document.getElementById('Text1').value);
	                                var
second_number=parseFloat(document.getElementById('Text2').value);
                                var myResult=(first_number*second_number);

document.getElementById('txtresult').innerHTML = myResult;

                </script>

       </head>

       <body>
                <p>
<br/>
                        <label for"first number">Enter the first
number: </label>
                        <input type="text" title="Enter first number:"
label="first number" alt="first number" name="first number" id="Text1"
/><br/>
                        <label for"operation">Choose operation: </label>
<select>
       <option>Add</option>	
                <option>Subtract</option>
<option>Multiply</option>
</select>

<br/>  <label for"2nd number">Enter the second number: </label>
                        <input type="text" title="2nd number"
id="Text2" onblur="function_calculater()"/><br/>
                        <button type="button" title="calculate"
name="calculate" onclick=" function
function_calculate");/>Calculate</button>
                </p>
                <p  style="font-size: xx-large; font-weight:
bolder;">result: <span id="txtresult"></span></p>
</body>
</html>


On 11/25/16, Aaron Cannon via nfbcs <nfbcs at nfbnet.org> wrote:
> Nicole is correct.  the onclick attribute should only have the name of
> one function in it, and only the function name.  No parenthesis.
> onclick="function_calculate"
>
> Then, in that empty function_calculate function, you should call
> function_add, function_subtract, ETC. based on the value of the
> dropdown.
>
> Once you've got that working, I would suggest you refactor things a
> bit.  If you look at your function_add and function_subtract
> functions, you'll notice that they're mostly the same, except for one
> small part.  That's often a good indication that you should refactor.
> Basically, these functions should only do the operations they're named
> for.
>
> For example, for cleaner code, I would recommend making your
> function_add look like this:
>
> function function_add(first_number, second_number) {
>   return first_number + second_number;
> }
>
> In short, you should move all the logic to extract the first and
> second numbers from the form fields, and assigning the result, to
> function_calculate, so it's all in one place, and not repeated in
> multiple places.
>
> This is known as the dry principle.  Dry stands for do not repeat
> yourself.  Of course, it's nearly impossible to write a completely dry
> program, and sometimes taking it to extreme can make your code harder
> to work with, but it's definitely something to strive towards, within
> reason.
>
> Aaron
>
> On 11/24/16, Nicole Torcolini via nfbcs <nfbcs at nfbnet.org> wrote:
>> The problem is that your button does not know which function to perform.
>> You
>> need to have a separate function for your button that checks which option
>> is
>> selected and then calls the associated function.
>>
>> -----Original Message-----
>> From: nfbcs [mailto:nfbcs-bounces at nfbnet.org] On Behalf Of Taylor Arndt
>> via
>> nfbcs
>> Sent: Thursday, November 24, 2016 6:30 PM
>> To: NFB in Computer Science Mailing List
>> Cc: Taylor Arndt
>> Subject: [nfbcs] More help with javascript calculater
>>
>> Hi,
>> So i got some of my calculater
>>
>> --
>>  Taylor
>>
>>  to work, but it seems like subtraction is the only thing it wants to do
>> now, and i want to implament all 4 functions Here is the code:
>> <!DOCTYPE html
>>  PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
>> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
>> <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
>>         <head>
>>                 <title>Accessible calculator</title>
>>
>>                 <script>
>>  function function_calculate(){
>>  }
>> function function_add()
>>  {
>>   var first_number=parseFloat(document.getElementById('Text1').value);
>>                                 var
>> second_number=parseFloat(document.getElementById('Text2').value);
>>            var myResult=(first_number+second_number);
>> document.getElementById('txtresult').innerHTML = myResult; }
>>
>> function function_subtract()
>>  {
>>   var first_number=parseFloat(document.getElementById('Text1').value);
>>                                 var
>> second_number=parseFloat(document.getElementById('Text2').value);
>>            var myResult=(first_number-second_number);
>> document.getElementById('txtresult').innerHTML = myResult; }
>>
>>                 </script>
>>        </head>
>>
>>        <body>
>>                 <p>
>> <br/>
>>                         <label for"first number">Enter the first
>> number: </label>
>>                         <input type="text" title="Enter first number:"
>> label="first number" name="first number" id="Text1" /><br/>
>>                         <label for"operation">Choose operation: </label>
>> <select>
>>        <option>Add</option>	
>>                 <option>Subtract</option> <option>Multiply</option>
>> <option>Divide</option> </select>
>>
>> <br/>  <label for"2nd number">Enter the second number: </label>
>>                         <input type="text" title="2nd number"
>> id="Text2"/><br/>
>>         <button type="button" title="calculate" name="calculate"
>> onclick=" function_calculate();  function_add(); function_subtract();
>> function_multiply(); function_divide(); "/>Calculate</button>
>>                 </p>
>>                 <p  style="font-size: xx-large; font-weight:
>> bolder;">result: <span id="txtresult"></span></p> </body> </html>
>>
>> Thanks for all the help, and i apreciat it
>>
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>
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-- 
Taylor




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