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Remove Options from a Combo Box Using JavaScript

2,111 bytes added, 15:30, 12 June 2014

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You can use a JavaScript function to modify the options available in a pull-down box on the page.

==Remove One or More Options==''Example 1,'' The following example removes two different [[Types]] available for new '''Level 2''' records(useful if you need to define complex criteria for what type of Level 2 records can be created):

<pre>

function RemoveTypes() {

var i=0;

var frm = document.forms[0]frmevent;// at Level 1 use document.form1 instead of document.forms[0]frmevent 

if (frm.eventid.value==0)

// Note: this loop starts at the bottom to avoid skipping any due to re-indexing as they are removed.

for (i=frm.eventtype.options.length-1;i>=0;i--)

{

if (frm.eventtype.options[i].text=='FirstType' || frm.eventtype.options[i].text=='SecondType') frm.eventtype.options[i]=null;}}}RemoveTypes(); </pre> ''Example 2,'' The following example removes a Branch on '''Level1''' from the Branch drop down list. <pre>function RemoveBranches(){var i=0;var frm=document.form1;// Note: this loop starts at the bottom to avoid skipping any due to re-indexing as they are removed.for(i=3;i>=0;i--){ if (frm.eventtypebranchid.options[i].textvalue=='SecondType448060') //448060 is a Branch id frm.eventtypebranchid.options[remove(i]=null);}

}

RemoveBranches();

 

</pre>

 

''Example 3,''

 

The following example also removes Branches on '''Level1''' from the Branch drop down list.

 

<pre>

function RemoveBranches()

{

var i=0;

var frm=document.form1;

if(frm){

// Note: this loop starts at the bottom to avoid skipping any due to re-indexing as they are removed.

for(i=(frm.branchid.options.length-1);i>=0;i--){

if (frm.branchid.options[i].value!=1111 && frm.branchid.options[i].value!=2222 && frm.branchid.options[i].value!=3333 &&frm.branchid.options[i].value!=4444){

frm.branchid.remove(i);

}

}

}

}

RemoveTypesRemoveBranches(); </pre> If you wish to control this by [[Role|role]] (for example if you want a role to be able to view existing Level 2 records of a given [[Type]], but not create them...) Include this in the variable section at the top of the script: var myrolelist="@me.rolelist@"; And replace or include the following in the if logic section: if (myrolelist.indexOf(",1234,")>=0) ::''Note that you must test for greater than or equal to 0. If the role is the first listed in the [[User|user]]'s role list it will return a 0 rather than a 1 because of the preceding comma.''

==To Remove All Options Except the Selected==

* The following script will prevent users from changing the Level 2 Type once the record has been saved:

<pre>

// For existing Types remove all options from the Type field (except the selected) so it can't be changed

if (frm.eventid.value!=0)

{

for (i=frm.eventtype.options.length-1;i>=0;i--)

{

if (frm.eventtype.options[i].value!=frm.eventtype.value)

frm.eventtype.options[i]=null;

}

}

</pre>

'''Note:''' the same syntax can be used at Level 1, replacing '''document.forms[0]''' with '''document.form1'''

==See Also==

* [[Add Options to a Combo Box Using JavaScript]]

* [[Conditional Lists of Values]]

[[Category:JavaScript]]

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Arthur Lathrop

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