Even though the string is recognised as text, it cannot be searched using the searchForText method.

Thanks for replying.
I will send you the code I have created.

var targetTexts = ["LD", "MBR", "BR", "BR1", "BR2"];
var grayColor = color.rgb(192, 192, 192); 

for (var pageNum = 0; pageNum < this.numPages; pageNum++) {
var page = this.getPage(pageNum);

page.searchForText({
text: targetTexts.join("|"), 
caseSensitive: false,
wholeWordsOnly: true, 
}).forEach(function(searchResult) {

searchResult.textColor = grayColor;
});
}