JavaScript: case-insensitive search

Answer 1

Yeah, use .match, rather than .search. The result from the .match call will return the actual string that was matched itself, but it can still be used as a boolean value.

var string = "Stackoverflow is the BEST";
var result = string.match(/best/i);
// result == 'BEST';

if (result){
    alert('Matched');
}

Using a regular expression like that is probably the tidiest and most obvious way to do that in JavaScript, but bear in mind it is a regular expression, and thus can contain regex metacharacters. If you want to take the string from elsewhere (eg, user input), or if you want to avoid having to escape a lot of metacharacters, then you're probably best using indexOf like this:

matchString = 'best';
// If the match string is coming from user input you could do
// matchString = userInput.toLowerCase() here.

if (string.toLowerCase().indexOf(matchString) != -1){
    alert('Matched');
}

Answer 2

var result= string.search(/searchstring/i);

replace with:

var result= string.search(new RegExp(searchstring, "i"));

Answer 3

If you're just searching for a string rather than a more complicated regular expression, you can use indexOf() - but remember to lowercase both strings first because indexOf is case sensitive:

var string="Stackoverflow is the BEST"; 
var searchstring="best";

// lowercase both strings
var lcString=string.toLowerCase();
var lcSearchString=searchstring.toLowerCase();

var result = lcString.indexOf(lcSearchString)>=0;
alert(result);

Or in a single line:

var result = string.toLowerCase().indexOf(searchstring.toLowerCase())>=0;

Answer 4

If you are concerned about the "unterminated character class" case, removing all non-alphanumeric chars would be helpful:

searchstring = searchstring.replace(/[^a-zA-Z 0-9]+/g,'');