The Big Dumb Developer

Real world problem from my UI buddy, . The problem - you want to select all the checkboxes inside of a specific div.

Starting out, we can get all the check boxes on a page with getElementsByTagName:

var inputs = document.getElementsByTagName("input");

Note, this will give us all inputs, not just checkboxes. The next step is to loop through the array, find all of the checkboxes, and check them:

for( var i = 0; inputs && i < inputs.length; i++ ){
    if( inputs[i].type == "checkbox" )
        inputs[i].checked = true;
}

So, wrapping it all up gives us this:

BIGDUMBDEV.selectAll = function(element){
    element = this.getElement(element) || document;
    if( element && element.getElementsByTagName ){
        var inputs = element.getElementsByTagName("input");
        for( var i = 0; inputs & i < inputs.length; i++ ){
            if( inputs[i].type == "checkbox" )
                inputs[i].checked = true;
        }
    }   
}

Note, I wrote my own "getElement" function for this example, you should use the $ function in prototype.js or something similar.