]po[ Javascript / jQuery Cheat Sheet

Get form:

var oForm = document.getElementById('project-ae');

Browse through elements of a form:

          for (i = oForm.cost_object_category_id.options.length-1; i >= 0; i--) {
                oForm.cost_object_category_id.remove(i);
            }

Check existence of element:

if (document.getElementById("sideBarTab") != null) {
...
}

Get element:

document.getElementById('slave_content').style.visibility='visible';

Get element attribute:

document.getElementById('sidebar').getAttribute('savedHeight')

Inserting elements:

var node_insert_after=document.getElementById("slave");
var node_to_move=document.getElementById("fullwidth-list");
document.getElementById("monitor_frame").insertBefore(node_to_move, node_insert_after.nextSibling);

Get value of a drop down in a form:

var oForm = document.getElementById(‘project-ae’);
var company_id = oForm.elements["company_id"].options[oForm.elements["company_id"].selectedIndex].value;