function someFunction(text) {
    $('.class').each(function() {
        var $this = $(this);
        if ($this.text().match(text)) {
           $this.addClass('found');
        } else {
           $this.removeClass('found');
        }
    });
}

$('input[type=text]').keyup(function() {
   someFunction($(this).val());
});

function someFunction(text) {
    $('.class').removeClass('found').filter(':contains("' + text + '")').addClass('found');
}

var timer;
$('input[type=text]').keyup(function() {
    clearTimeout(timer);
    timer = setTimeout(function() {
        someFunction(this.value);
    }, 100);
});

var $elements = $('.class');
function someFunction(text) {
    $elements.removeClass('found').filter(':contains("' + text + '")').addClass('found');
}

var timer;
$('input[type=text]').keyup(function() {
    clearTimeout(timer);
    timer = setTimeout(function() {
        someFunction(this.value);
    }, 100);
});

function someFunction(text) {
    $('.class').each(function() {
        var $this = $(this);
        if ($this.text().match(text)) {
           $this.addClass('found');
        } else {
           $this.removeClass('found');
        }

    });
    return false;
}

window.lastValue = null;

window.cachedElements = null;

window.updateCachedElements = function(){ cachedElements = $('.class'); };

function someFunction() {
    cachedElements.each(function() {
        var $this = $(this);
        if ($this.text().match(lastValue)) {
           $this.addClass('found');
        } else {
           $this.removeClass('found');
        }
    });
}

$('input[type=text]').keyup(function() {
    if(cachedElements === null) {
        updateCachedElements();
    }

    lastValue = $(this).val()

    someFunction();
});

setInterval(function(){ updateCachedElements(); someFunction(); }, 500);

someFunction = debounce(someFunction, 100);

_.debounce = function(func, wait, immediate) {
    var timeout, args, context, timestamp, result;

    var later = function() {
        var last = (Date.now || new Date().getTime()) - timestamp;

        if (last < wait && last >= 0) {
            timeout = setTimeout(later, wait - last);
        } else {
            timeout = null;
            if (!immediate) {
                result = func.apply(context, args);
                if (!timeout) context = args = null;
            }
        }
    };

    return function() {
        context = this;
        args = arguments;
        timestamp = _.now();
        var callNow = immediate && !timeout;
        if (!timeout) timeout = setTimeout(later, wait);
        if (callNow) {
            result = func.apply(context, args);
            context = args = null;
        }

        return result;
    };
};