help with JavaScript function

[Alex Kravets]

I am new to JavaScript and wanted to get some help. I found this code to format decimal fields:

input type='text' 
          id='cp' 
          name='cp' 
          value='' size='11' 
          maxlength='11' 
          onchange="this.value = parseFloat(this.value).toFixed(2)" class="input"

What I want to do is put onChange event into a separate function and also be able to enter characters: less than, greater than or equal. Right now when I enter these characters I get NaN. Also, if I leave field empty and focus to another field I also get NaN, is there a workaround?

thanks a lot,
Alex

[Eric Pascarello]

NaN means not a number so when you add a non number character to the field it will throw an error.

[Alex Kravets]

thanks.
But how do I put the whole thing in a function?

[Bear Bibeault]

Something along the lines of:

onchange="onChangeWhatever(this)"  

and

function onChangeWhatever( element ) {
  element.value = parseFloat( element.value ).toFixed( 2 );
}

Now you can muck with the function to put in your checks for special cases.

[Eric Pascarello]

If they are in the JavaScript method, it will not work...
What are you trying to do?

[Yuriy Fuksenko]

<input ..... onchange="doFormat(this)">
<script>
function doFormat(elm){
  var val = parseFloat(elm.value);
  if(isNaN(val)){
     //error handling
     alert('value is incorrect');
  }
  else{
    elm.value = val.toFixed(2);
  }
}
</script>

[Alex Kravets]

thanks.
This is what I got:

function DecimalFormat(element,fixed){
         var val = element.value;
 
         if(val.substring(0,1) == '>' || val.substring(0,1) == '<'){
                val =  parseFloat( element.value.substring(1,val.length()) ).toFixed(fixed);
                element.value = val.substring(0,1) + val;
         }
         else
                element.value = parseFloat( element.value ).toFixed(fixed);
         if(isNaN(element.value)){
                element.value = '';
         }
}

This work ok, except that at line:

element.value = val.substring(0,1) + val;

I get error Function Expected, why do I get this error?

[Yuriy Fuksenko]

Try to change

 element.value = val.substring(0,1) + val;

to

element.value = String.valueOf(val).substring(0,1) + val;

[Alex Kravets]

nope, same thing...I tried to use eval, but it does not work either.

[Yuriy Fuksenko]

try to use substr instead of substring

 stringvar.substr(start [, length ]) 

[Alex Kravets]

aren't they the same thing?

[Eric Pascarello]

The substring() method accepts two parameters to determine where to take the partial string from. The parameters are placed in parentheses separated by a comma. The first parameter is the initial point to start the cut. The second parameter decides where to end the cut.

This substr() method contains two parameters that are placed between the parentheses. The first parameter is the character where the copying of the substring begins. The second parameter is the number of places you want copied instead of the ending location.

Therfore the two are not the same thing....
Eric

[Alex Kravets]

ok, so what do square brackets mean in
stringvar.substr(start [, length ]) ?

[Bear Bibeault]

It means the 2nd parameter is optional.