jQuery find and replace string

You could do something like this:

$("span, p").each(function() {
    var text = $(this).text();
    text = text.replace("lollypops", "marshmellows");
    $(this).text(text);
});

It will be better to mark all tags with text that needs to be examined with a suitable class name.

Also, this may have performance issues. jQuery or javascript in general aren't really suitable for this kind of operations. You are better off doing it server side.

You could do something this way:

$(document.body).find('*').each(function() {
    if($(this).hasClass('lollypops')){ //class replacing..many ways to do this :)
        $(this).removeClass('lollypops');
        $(this).addClass('marshmellows');
    }
    var tmp = $(this).children().remove(); //removing and saving children to a tmp obj
    var text = $(this).text(); //getting just current node text
    text = text.replace(/lollypops/g, "marshmellows"); //replacing every lollypops occurence with marshmellows
    $(this).text(text); //setting text
    $(this).append(tmp); //re-append 'foundlings'
});

example: http://jsfiddle.net/steweb/MhQZD/

Below is the code I used to replace some text, with colored text. It's simple, took the text and replace it within an HTML tag. It works for each words in that class tags.

$('.hightlight').each(function(){
    //highlight_words('going', this);
    var high = 'going';
    high = high.replace(/\W/g, '');
    var str = high.split(" ");
    var text = $(this).text();
    text = text.replace(str, "<span style='color: blue'>"+str+"</span>");
    $(this).html(text);
});

You could do something like this:

HTML

<div class="element">
   <span>Hi, I am Murtaza</span>
</div>

jQuery

$(".element span").text(function(index, text) { 
    return text.replace('am', 'am not'); 
});