Forms >>> No Duplicates.


		<script 
		language="javascript"
		type="text/javascript">

		/* Visit http://www.yaldex.com/ 
		for full source code

		and get more free JavaScript, CSS and DHTML scripts! */

		<!-- Begin

		var 
		OptLstTxt =
		new
		Array;

		var 
		OptLstVal =
		new
		Array;

		var 
		OptLen =
		0;

		function 
		NoDupl(SelObjFrom, 
		SelObjTo)
		{

		var 
		OldToVal = 
		SelObjTo.options[SelObjTo.selectedIndex].value;

		if
		(OptLen
		==
		0)
		{

		OptLen 
		= 
		SelObjFrom.length;

		for
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		i =
		1; 
		i < 
		OptLen; 
		i++)
		{

		OptLstTxt[i]
		= 
		SelObjFrom.options[i].text;

		OptLstVal[i]
		= 
		SelObjFrom.options[i].value;

		   
		}

		}

		var 
		j =
		1;

		for
		(var 
		i =
		1; 
		i < 
		OptLen; 
		i++)
		{

		if
		(OptLstVal[i]
		!= 
		SelObjFrom.options[SelObjFrom.selectedIndex].value)
		{

		if
		(j
		== 
		SelObjTo.length)
		{

		SelObjTo.options[j]
		=
		new
		Option(OptLstTxt[i]);

		}

		else
		{

		SelObjTo.options[j].text
		= 
		OptLstTxt[i];

		}

		SelObjTo.options[j].value
		= 
		OptLstVal[i];

		if
		(OptLstVal[i]
		== 
		OldToVal)
		{

		SelObjTo.selectedIndex
		= 
		j;

		}

		j++;

		   
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		(SelObjTo.length
		> 
		j)

		SelObjTo.options[(SelObjTo.length
		-
		1)]
		=
		null;

		}

		//  End -->

		</script>

		<form
		method="POST"
		name="MForm">

		Try to select the same color:

		<br>

		<nobr>

		<select
		name="Color_1"
		onChange="NoDupl(this,document.MForm.Color_2)">

		<option 
		selected
		value=''>Select 
		your first prefered color</option>

		<option 
		value='R'>Red</option>

		<option 
		value='J'>Yellow</option>

		<option 
		value='G'>Green</option>

		<option 
		value='B'>Blue</option>

		</select>

		<select 
		name="Color_2"
		onChange="NoDupl(this,document.MForm.Color_1)">

		<option 
		selected
		value=''>Select 
		Second Prefered color</option>

		<option 
		value='R'>Red</option>

		<option 
		value='J'>Yellow</option>

		<option 
		value='G'>Green</option>

		<option 
		value='B'>Blue</option>

		</select>

		</nobr>

		</form>