Expiring Today—Celebrate National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

Javascript issue with document.forms function

Posted on 2011-09-07
5
Medium Priority
?
384 Views
Last Modified: 2012-06-21
I'm having an issue with the document.forms function in this java-script , but I cannot seem to find the issue.  This is my first foray into any real java-script.   the first drop down to field translation works correctly, but none of the additional fields will auto populate with the defined value.  Any help would be greatly appreciated.

<head>
<title>TEST</title>
</head>

<body>

<script type="text/javascript">
if(window.addEventListener){
window.addEventListener('load',switchme,false);
}
else { 
if(window.attachEvent){
window.attachEvent('onload',switchme);
}
}

function switchme(){
df=document.forms[0];
df[0].onchange=function(){
switch(this.value) {
case 'A':
df[1].value='Item  1';
break;
case 'B':
df[1].value='Item  2';
break;
case 'C':
df[1].value='Item  3';
break;
case 'D':
df[1].value='Option 1';
break;
case 'E':
df[1].value='Option 2';
break;
default:
df[1].value='';
break;
}
}
}
</script>

<form action="#" method="get">
<div>
	<table align="center" style="width: 500px">
		<tr>
			<td>
<select name="1type">
<option value="[none]" selected="selected">---</option>
	<option value="A">Item</option>
	<option value="D">Option ?</option>
	<option value="E">Option ?</option>
</select></td>
			<td>
<input name="1value" type="text"/>
			</td>
		</tr>
		<tr>
			<td>
<select name="2type">
<option value="[none]" selected="selected">---</option>
	<option value="B">Item</option>
	<option value="D">Option ?</option>
	<option value="E">Option ?</option>
</select></td>
			<td>
<input name="2value" type="text"/>
			</td>
		</tr>
		<tr>
			<td>
<select name="3type">
<option value="[none]" selected="selected">---</option>
	<option value="C">Item</option>
	<option value="D">Option ?</option>
	<option value="E">Option ?</option>
</select></td>
			<td>
<input name="3value" type="text"/>
			</td>
		</tr>
	</table>
</div>
</form>

</body>

Open in new window

0
Comment
Question by:mcarter1953
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
5 Comments
 
LVL 82

Expert Comment

by:leakim971
ID: 36499535
the onchange attribute is only set to the first dropdown (form element with index 0)
the first dropdown have options with the following value : A,D and E

your switch only change the value of the second textbox (form element with index 1)

so everything run fine
if you want to handle onchange event for the other dropdown set :
df[2].onchange (the second dropdown)
and
df[4].onchange (the third dropdown)
0
 
LVL 82

Expert Comment

by:hielo
ID: 36499547
document.forms[0]

refers to the first <FORM> in your document. From what I can guess, what you are interested in is in the onchange event of the SELECT lists:
function switchme(){
	var df=document.forms[0].getElementsByTagName('SELECT');
	df[0].onchange=function(){
		alert( 'selected ' + this.value )

//it's not clear to me what you are trying to do in the switch
//otherwise I would offer more help
		switch(this.value) {
		case 'A':
			df[1].value='Item  1';
			break;
		case 'B':
			df[1].value='Item  2';
			break;
		case 'C':
			df[1].value='Item  3';
			break;
		case 'D':
			df[1].value='Option 1';
			break;
		case 'E':
			df[1].value='Option 2';
			break;
		default:
			df[1].value='';
			break;
		}
	}
}

Open in new window

0
 
LVL 82

Expert Comment

by:hielo
ID: 36499622
read comments in code and try it:
function switchme(){
	//here f will hold a reference to the <FORM> object
	var f=document.forms[0];

	//get an array of your selects
	var selectList=f.getElementsByTagName('SELECT');

	//iterate through list and attach the onchange to each of them
	for(var i=0,limit=selectList.length; i < limit; ++i)
	{
		selectList[i].onchange=function(){
			//when your selected item is from list name="1type", then prefix will have 1
			//when your selected item is from list name="2type", then prefix will have 2
			//when your selected item is from list name="3type", then prefix will have 3
			var prefix=this.name.charAt(0);

    		switch(this.value) {
	    		case 'A':
					//again f is a reference to <FORM>
					//since the form contains <input name="1value"..>
					//you can access/reference THAT specific input with:
					//	f['1value']
					//If you want to set the value of THAT input to say 3, then 
					//just append the ".value" attribute and assign it 3
					//	f['1value'].value=3
					//Knowing that, you can then just dynamically "construct" the "1value"
					//by using the prefix variable above, which leads you to the statement below
					//and now it works for all the selects
    				f[prefix+'value'].value='Item  1';

    				break;

					//the comments in case 'A' apply to the rest
    			case 'B':
    				f[prefix+'value'].value='Item  2';
	    			break;
    			case 'C':
    				f[prefix+'value'].value='Item  3';
    				break;
	    		case 'D':
    				f[ prefix+'value'].value='Option 1';
    				break;
    			case 'E':
    				f[prefix+'value'].value='Option 2';
	    			break;
    			default:
    				f[prefix+'value'].value='';
    				break;
    		}
		}
	}
}

Open in new window

0
 
LVL 82

Accepted Solution

by:
leakim971 earned 2000 total points
ID: 36499634
Check this : http://jsfiddle.net/QUvd5/
if(window.addEventListener){
    window.addEventListener('load',switchme,false);
}
else { 
    if(window.attachEvent){
        window.attachEvent('onload',switchme);
    }
}

function switchme(){
    df=document.forms[0];
    df[0].onchange = new Function("switchx(this.value,1)");
    df[2].onchange = new Function("switchx(this.value,3)");
    df[4].onchange = new Function("switchx(this.value,5)");
}

function switchx(x,n){
    switch(x) {
        case 'A':
            df[n].value='Item  1';
            break;
        case 'B':
            df[n].value='Item  2';
            break;
        case 'C':
            df[n].value='Item  3';
            break;
        case 'D':
            df[n].value='Option 1';
            break;
        case 'E':
            df[n].value='Option 2';
            break;
        default:
            df[n].value='';
            break;
    }
}

Open in new window

0
 

Author Closing Comment

by:mcarter1953
ID: 36499664
thanks for the help, great fix :)
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Find out what you should include to make the best professional email signature for your organization.
Originally, this post was published on Monitis Blog, you can check it here . Websites are getting bigger and more complicated by the day. Video, images and custom fonts are all great for showcasing your product or service. But the price to pay in…
In this tutorial viewers will learn how to style a corner ribbon overlay for an image using CSS Create a new class by typing ".Ribbon":  Define the class' "display:" as "inline-block": Define its "position:" as "relative": Define its "overflow:" as …
Video by: Mark
This lesson goes over how to construct ordered and unordered lists and how to create hyperlinks.

719 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question