Javascript: set an onChange function by javascript, not embedded.

3 New Member

I have an HTML file that includes a JavaScript. I would like this JavaScript to be able to create an "onChange=<func tion>" attribute against the password element.

Here is an example page of the onChange embedded in the "password" field. This is normal HTML and it works fine.

Expand|Select|Wrap|Line Numbers

 <HTML>

<HEAD><TITLE> Example of onChange Event Handler </TITLE>
 
</HEAD>

<BODY BGCOLOR="FFFFFF" TEXT="000000">

<H3>Example of onChange Event Handler</H3>

<form method="post">

    Name: <input type="text" name="name" size=10><br>

    Pass: <input type="password" name="password" size=10 onChange='alert("It WORKED!")'><br>

<input type="submit" name="submit" size=10 >

</form>

<P>

</BODY>

</HTML>

However, I would like to be able to add the "onChange" method by JavaScript. This way I can dynamically change the method being used. Here is my attempt at getting it to work. This does not work but shows what I am trying to do.

Expand|Select|Wrap|Line Numbers

 <HTML>

<HEAD><TITLE> Example of onChange Event Handler </TITLE>
 
<SCRIPT LANGUAGE="JavaScript">

document.forms[0].elements[1].onChange='alert("It WORKED!")';

</SCRIPT>
 
</HEAD>

<BODY BGCOLOR="FFFFFF" TEXT="000000">

<H3>Example of onChange Event Handler</H3>

<form method="post">

    Name: <input type="text" name="name" size=10><br>

    Pass: <input type="password" name="password" size=10 ><br>

<input type="submit" name="submit" size=10 >

</form>

<P>

</BODY>

</HTML>

Jun 6 '07 #1

Subscribe Reply

47970

r035198x

13,262

MVP

I have an HTML file that includes a JavaScript. I would like this JavaScript to be able to create an "onChange=<func tion>" attribute against the password element.

Here is an example page of the onChange embedded in the "password" field. This is normal HTML and it works fine.

Expand|Select|Wrap|Line Numbers

<HTML>

<HEAD><TITLE> Example of onChange Event Handler </TITLE>

</HEAD>

<BODY BGCOLOR="FFFFFF" TEXT="000000">

<H3>Example of onChange Event Handler</H3>

<form method="post">

    Name: <input type="text" name="name" size=10><br>

    Pass: <input type="password" name="password" size=10 onChange='alert("It WORKED!")'><br>

<input type="submit" name="submit" size=10 >

</form>

<P>

</BODY>

</HTML>

However, I would like to be able to add the "onChange" method by JavaScript. This way I can dynamically change the method being used. Here is my attempt at getting it to work. This does not work but shows what I am trying to do.

Expand|Select|Wrap|Line Numbers

<HTML>

<HEAD><TITLE> Example of onChange Event Handler </TITLE>

<SCRIPT LANGUAGE="JavaScript">

document.forms[0].elements[1].onChange='alert("It WORKED!")';

</SCRIPT>

</HEAD>

<BODY BGCOLOR="FFFFFF" TEXT="000000">

<H3>Example of onChange Event Handler</H3>

<form method="post">

    Name: <input type="text" name="name" size=10><br>

    Pass: <input type="password" name="password" size=10 ><br>

<input type="submit" name="submit" size=10 >

</form>

<P>

</BODY>

</HTML>

Put the code in a function and call that function onChange of the password box.

Jun 6 '07 #2

dmjpro

2,476

Top Contributor

Welcome to TSDN.

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<SCRIPT LANGUAGE="JavaScript">

//document.forms[0].elements[1].onChange='alert("It WORKED!")';

//Here the function reference requires not the string.

//Edit the line like this .....

document.forms[0].elements[1].onChange=function(){alert("It WORKED!")};

</SCRIPT>

Now see the effect.
Have a good day.

Kind regards,
Dmjpro.

Jun 6 '07 #3

auslandt

New Member

Welcome to TSDN.

Expand|Select|Wrap|Line Numbers

<SCRIPT LANGUAGE="JavaScript">

//document.forms[0].elements[1].onChange='alert("It WORKED!")';

//Here the function reference requires not the string.

//Edit the line like this .....

document.forms[0].elements[1].onChange=function(){alert("It WORKED!")};

</SCRIPT>

Now see the effect.
Have a good day.

Kind regards,
Dmjpro.

Thanks for the reply. However, this does not work either.

Jun 6 '07 #4

auslandt

New Member

Thanks for the reply. However, this does not work either.

I found the problem. Your example DOES work, but not if the <SCRIPT> is in the <HEAD>. I believe what happens is that this function is loaded prior to the elements existing.

I moved this snippet to the BOTTOM of the file; after the </HTML> and it worked. Likely because the elements finally do exist so the onChange assignment acutally gets set.

Thanks!

- Matt

Jun 6 '07 #5

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