How to locate the tags that contain blanks at the start of the tag content using an ACL fucntion

I would say the easiest way to do this is using XPath, something like this:

function fixSpaces() {
 local oids[], o;
 xpath_nodeset(oids, "//*[starts-with(text(),' ')]");
 for (o in oids) {
 # do something with oids[o]...
 }
}