Hiding Controls through Scriptin

Hi All,

we want to hide controls(images to be specific) based on the dataset.
for example in the below image the check boxes in front of Mr. and Mrs.
are images(as Birt does not provide default CheckBox Functionality)
based on the data sale row["SALUTATION"]='Mr.' only image in front
of Mr. should be shown and the Image in front of the Mrs. should be hidden.

we tried googled alot.
we tried the below code
onFetch event of Dataset:

var SAL= this.getRowData().getExpressionValue("row["SALUTATION"]");

reportContext.setPersistentGlobalVariable("SAL1", SAL);


beforeRender of rptdesing :

var SAL2= reportContext.getPersistentGlobalVariable('SAL1');
if(SAL2 == 'Mr.')
{
reportContext.getDesignHandle().getElementByID(65).visibilty= true;
}
else
{
reportContext.getDesignHandle().getElementByID(65).visibilty=false;
}

Kindly guide us how this could be achieved.