Member Avatar for 68thorby68

I have read through loads of comments about how and why object expected can be reported, but I think my problem is that my javascript and calls are rubbish.

I want to build a simple function that, if I de-select the first check box, all other checkboxes are de=seleceted, or if I select one of the other checkboxes and not the forst check box, the first checkbox will automatically be selected.

I have this working fine when i use the checkbox input name in the javascript (all checkboxes except the first have the same name), but as I want to pass each input to a php function for processing, so I need different input names. So, in my wisdom, I thought why not add an id to each field and use the GetElementById function.

below is my attempt: ANY advice is more than welcome. Thank you.

<head>
<SCRIPT text/javascript>

function Check1(chk)
{
if(document.myform3.Check_ctr.checked==false){
	chk.checked = false ;
}
}

function Check2(chk)
{
chk.checked=true;
}

</script>
<body>
<form name="myform3" method="post" action="post_php">
<table align="center" width="370px" border="0">
<tr>
	<td width="250px">Item</td>
	<td  align="center" valign="middle">Tick to Display</td>
</tr>
<tr>    
        <td>Project Name: </td>
        <td align=center valign=middle><input type="checkbox" name="Check_ctr" value="yes" onclick="Check1(document.myform3.getElementById('check_list'))" /></td>
</tr>
<tr>
	<td>&nbsp;</td>
	<td valign=middle align=center><input type="checkbox" name="checkbox" value="1" id="check_list" onclick="check2(document.myform3.Check_ctr)"/></td>						
</tr>
<tr>
	<td>&nbsp;</td>
	<td valign=middle align=center><input type="checkbox" name="checkbox" value="1" id="check_list" onclick="check2(document.myform3.Check_ctr)"/></td>
</tr>
<tr>							
	<td>&nbsp;</td>
	<td valign=middle align=center><input type="checkbox" name="checkbox" value="1" id="check_list" onclick="check2(document.myform3.Check_ctr)"/></td>
</tr>
</table>
<input type="submit" name="submit" value="Save Changes" />
Edited by 68thorby68 because: n/a
  • 2 Contributors
  • 5 Replies
  • 119 Views
  • 20 Hours Discussion Span
  • Latest Post Latest Post by 68thorby68
Member Avatar for urtrivedi

First thing is you must write
Check2(document.myform3.Check_ctr) instead of
check2(document.myform3.Check_ctr) (Capital C in check2 because javascript is case sensitive.

I have changed whole code as following, keeping name and ID same, using checkbox array (easy to process in php after submission)

<head>
<SCRIPT text/javascript>

function Check1()
{
  var intCounter = 0;
   for(intCounter=0;intCounter<=document.myform3.elements.length-1;intCounter++)
    {
      if(document.myform3.elements[intCounter].type=="checkbox")
      {
          document.myform3.elements[intCounter].checked= document.myform3.Check_ctr.checked ;
       }
   }
}

function Check2(chk)
{
	
	if (chk.checked)
  	  document.myform3.Check_ctr.checked =true;
}

</script>
<body>
<form name="myform3" method="post" action="post_php">
<table align="center" width="370px" border="0">
<tr>
	<td width="250px">Item</td>
	<td  align="center" valign="middle">Tick to Display</td>
</tr>
<tr>    
        <td>Project Name: </td>
        <td align=center valign=middle><input type="checkbox" name="Check_ctr" id ="Check_ctr" value="yes" onclick="Check1()" /></td>
</tr>
<tr>
	<td>&nbsp;</td>
	<td valign=middle align=center><input type="checkbox" name="check_list[]" value="1" id="check_list[]" onclick="Check2(this)"/></td>						
</tr>
<tr>
	<td>&nbsp;</td>
	<td valign=middle align=center><input type="checkbox" name="check_list[]" value="1" id="check_list[]" onclick="Check2(this)"/></td>
</tr>
<tr>							
	<td>&nbsp;</td>
	<td valign=middle align=center><input type="checkbox" name="check_list[]" value="1" id="check_list[]" onclick="Check2(this)"/></td>
</tr>
</table>
<input type="submit" name="submit" value="Save Changes" />
Member Avatar for 68thorby68

Thank you urtrivedi,

This is quite amazing. I don't really understand everything that is going on in the line

for(intCounter=0;intCounter<=document.myform3.elements.length-1;intCounter++)

, however that will be my research project for today.

Many thanks for your invaluable help.

Member Avatar for urtrivedi

this loop will go through all the elements in the form and one by one.

Member Avatar for 68thorby68

Many thanks urtrivedi,

I have found one small problem though, even though I have given each checkbox a unique name i.e. 1check_list[] and 2check_list[], the value for Check2 is returned as an array, instead of the value. Is there anything I am doing wrong here?

Member Avatar for 68thorby68

Ah,

Got it, if I remove the square brackets from the name field (of course ensuring the name is unique, and ensure the square brackets remain for the ID, I get a value and not an array.

Many thanks.

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