Solved

Loop with Drop Down Box

Posted on 2008-10-27
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Last Modified: 2012-05-05
I have this javascript script and I am trying to compare values of one drop down to another one to make sure they are not the same selected value.

This is all being generated server side because I never know how many drop downs the user will have on the screen but each selected one has to be uniquely selected.  Can anyone help on how I can append the index passing in and the index from the loop to the script i am using to compare values with?




function CompairMappedData(compareDDIndex) {
 
for(i = 0; i < 52; i++){
 
// we do not want to compair to the same dd that we are passing in
if !(compairDDIndex == i) {
 
if ((document.Form1.Columns_" + compareDDIndex " +.options[document.Form1.Columns_" + compareDDIndex " +.selectedIndex].value) == (document.Form1.Columns_" + i " +.options[document.Form1.Columns_" + i " +.selectedIndex].value)) {
 
alert('You have selected this mapping for another column.\n\nThe mapping for each column must be unique.');
 
document.Form1.Columns_" + compareDDIndex " +.options[document.Form1.Columns_" + compareDDIndex " +.selectedIndex].value = ''
 
}
}
}
}

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Question by:Lantrax
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5 Comments
 
LVL 82

Expert Comment

by:hielo
ID: 22814019
refer to the following:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
 "http://www.w3.org/TR/html4/loose.dtd"> 
<html>
<head>
<title></title>
<script type="text/javascript">
//if it returns a non-zero string, there are duplicates
//the return value are indices of list2 that are duplicated in list1
function compareLists(list1,list2){
	var duplicate="";
	for( var i=0, iLimit=list1.options.length; i < iLimit; ++i)
	{
		for( var j=0, jLimit=list2.options.length; j < jLimit; ++j)
		{
			if( list1.options[i].selected && list2.options[j].selected && list1.options[i].value== list2.options[j].value )
				duplicate +=  ","+j;
		}
	}
return duplicate.substring(1);
}
</script>
</head>
<body>
<select name="alpha" id='alpha' multiple="multiple" onchange="alert( compareLists(this,beta) )"><option value='1'>a</option><option value='2'>b</option><option value='3'>c</option><option value='4'>d</option></select>
<select name="beta" id='beta' multiple="multiple"  onchange="alert( compareLists(alpha,this) )"><option value='1'>a</option><option value='2'>b</option><option value='3'>c</option><option value='4'>d</option></select>
</body>
</html>

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Author Comment

by:Lantrax
ID: 22814107
That script is a bit different from what I am trying to accomplish. The number of drop down boxes changes based on the user loading the page. There may be 50 or 100 drop downs on a page. Each one has to be unique. So I have server side code to loop through and generate the index to loop to in the for each loop. I pass in the drop down box being changed but the function needs to loop through all drop down boxes on the page and verify that non of them have the same option selected.

j
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LVL 82

Accepted Solution

by:
hielo earned 125 total points
ID: 22814189
try:
function CompairMappedData(compareDDIndex) {
	for(i = 0; i < 52; i++)
	{
		// we do not want to compair to the same dd that we are passing in
		if( !compairDDIndex == i )
		{
			var sel = document.Form1["Columns_" + compareDDIndex];
			var sel2= document.Form1["Columns_" + i];
			if( sel.options[ sel.selectedIndex ].value == sel2.options[ sel2.selectedIndex ].value ) 
			{
				alert('You have selected this mapping for another column.\n\nThe mapping for each column must be unique.');
				sel.options[ sel.selectedIndex ].value = '';
			}
		}
	}
}

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Author Comment

by:Lantrax
ID: 22814477
Thank you very much. I made a few changes although you put me on the right track. Thank you very much.



function CompareMappedData(compareDDIndex) {
 
    	var sel = document.Form1["Columns_" + compareDDIndex];
		// we do not want to compare if the selected index = 0 because that is the Ignore Column option.
 		if (sel.selectedIndex != 0 ) 
		{
			for (i = 0; i < 52; i++)
			{
					// we do not want to compare to the same dd that we are passing in
					if (parseInt(compareDDIndex) != parseInt(i) )
					{
							var sel2= document.Form1["Columns_" + i];
							if ( sel.options[ sel.selectedIndex ].value == sel2.options[ sel2.selectedIndex ].value ) 
							{
									alert('You have selected this mapping for another column.\n\nThe mapping for each column must be unique.');
									sel.selectedIndex = 0;
									break;
							}
					}
			}
		}
}

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LVL 82

Expert Comment

by:hielo
ID: 22814502
glad to help
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