understanding what i can do with onChange

**@SM** · Jul 20 '05, 02:18 PM

Re: understanding what i can do with onChange

dan baker a ecrit :[color=blue]
>
> I am pretty much a newbie with javascript, and would like to get a
> little clarification on what I can do with an onChange javascript
> event handler.[/color]

You can change the value of a read-only field via JavaScript
Except on my NC4.5 who doesn't know what is a readonly ...!

It is the only way to do it if you don't want to re-open (and php modify)

Try that :

<html>
<form>
<p><u><b>1st test :</b></u>
<p>a "virtual read only"
<input type=text name="onlyToRea d"
value="Some text to test"
onkeydown="truc =this.value;"
onkeyup="this.v alue=truc;">
<p>to modify the "virtual read only"
<br>Enter your text here :
<input type=text name="modificat or"
onchange="onlyT oRead.value=thi s.value;" >
and quit the field.
<hr>
<p><u><b>2nd test :</b></u>
<p>a "real read only"
<input type=text name="ToReadOnl y"
value="Some text to test"
readonly>
<p>to modify the "real read only"
<br>Enter your text here :
<input type=text name="modificat eur"
onchange="ToRea dOnly.value=thi s.value;" >
and quit the field.
<hr>
<input type=reset value="Reset">
</form></html>

No, you can't document.write on a document allready open
to be compatible with old browsers you must write in text-boxes or text-areas

If old browsers are not concerned
you can use the DOM

<html>
<form>
<p>a "writter on same document" :
<input type=text name="toWrite"
onchange="if(do cument.getEleme ntById)
document.getEle mentById('ToSee ').innerHTML=th is.value;">
<div id="ToSee"></div>
</form></html>

[color=blue]
> I have a dynamic page I build with perl and print to the browser which
> includes some data displayed and edittable in <FORM> elements. There
> are a couple areas where I display a message or a calculated total to
> the user based on the initial values of some data elements.
>
> I would like to clear or change the "read-only" messages and totals if
> certain FORM elements get changed... and am unsure how to approach
> this. It looks like if I display the "read-only" information in named
> FORM elements I could use onChange event handlers to set the values...
> but I don't really want the "read-only" or calculated fields to look
> like regular FORM elements or allow editting.[/color]

Yes you have (ie for my NC4.5) to use regular form element.
[color=blue]
> Is there a way to use onChange to either:
>
> - change the text in a specific area of a page that has already been
> loaded using document.write( ) ? I am totally unsure if I have an
> inline section of javascript that prints out a variable, and I change
> the variable via onChange, if the text displayed would change without
> refreshing the page.
>
> - put my "calculated " values in FORM elements that look like they are
> "read-only" but still allow me to change using the named object
> elements?
>
> thanks,
> d[/color]

--
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Stéphane MORIAUX : mailto:stephane OTER_MOImoriaux @wanadoo.fr
Aide aux Pages Perso (images & couleurs, formulaire, CHP, JS)

http://perso.wanadoo.fr/stephane.moriaux/internet/

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understanding what i can do with onChange

understanding what i can do with onChange

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