jsPsych/plugins/jspsych-likert.js
2013-03-20 21:12:28 -04:00

136 lines
3.7 KiB
JavaScript

/* jspsych-likert
* a jspsych plugin for measuring items on a likert scale
*
* Josh de Leeuw (March 2013)
*
*/
(function($) {
jsPsych.likert = (function(){
var plugin = {};
plugin.create = function(params) {
var trials = [];
for(var i = 0; i < params.questions.length; i++)
{
trials.push({
type: "likert",
questions: params.questions[i],
labels: params.labels[i],
intervals: params.intervals[i],
show_ticks: params.show_ticks || true
});
}
return trials;
}
plugin.trial = function(display_element, block, trial, part) {
// add likert scale questions
for(var i = 0; i < trial.questions.length; i++)
{
// create div
display_element.append($('<div>', { "id": 'likert'+i, "class": 'likertquestion'}));
// add question text
$("#likert"+i).append('<p class="likerttext likert">'+trial.questions[i]+'</p>');
// create slider
$("#likert"+i).append($('<div>', { "id": 'slider'+i, "class": 'slider likert' }));
$("#slider"+i).slider(
{
value: Math.ceil(trial.intervals[i] / 2),
min: 1,
max: trial.intervals[i],
step: 1
});
// show tick marks
if(trial.show_ticks) {
$("#likert"+i).append($('<div>', { "id": 'sliderticks'+i, "class": 'sliderticks likert', "css":{"position":'relative'} }));
for(var j = 1; j < trial.intervals[i]-1; j++){
$('#slider'+i).append('<div class="slidertickmark"></div>');
}
$('#slider'+i+' .slidertickmark').each(function(index)
{
var left = (index+1) * (100/(trial.intervals[i]-1));
$(this).css({
'position':'absolute',
'left': left+'%',
'width': '1px',
'height': '100%',
'background-color':'#222222'
});
});
}
// create labels for slider
$("#likert"+i).append($('<ul>', {"id": "sliderlabels"+i, "class": 'sliderlabels likert', "css":
{
"width":"100%",
"margin":"10px 0px 0px 0px",
"padding": "0px",
"display": "block",
"position": "relative"
}
}));
for(var j = 0; j < trial.labels[i].length; j++)
{
$("#sliderlabels"+i).append('<li>'+trial.labels[i][j]+'</li>');
}
// position labels to match slider intervals
var slider_width = $("#slider"+i).width();
var num_items = trial.labels[i].length;
var item_width = slider_width / num_items;
var spacing_interval = slider_width / (num_items - 1);
$("#sliderlabels"+i+" li").each(function(index){
$(this).css({
'display': 'inline-block',
'width': item_width+'px',
'margin': '0px',
'padding': '0px',
'text-align': 'center',
'position': 'absolute',
'left': (spacing_interval*index)-(item_width/2)
});
});
}
// add submit button
display_element.append($('<button>', {'id':'next','class':'likert'}));
$("#next").html('Submit Answers');
$("#next").click(function(){
// measure response time
endTime = (new Date()).getTime();
response_time = endTime-startTime;
// create object to hold responses
var question_data = {};
$("div.slider").each(function(index){
var id = "Q"+index;
var val = $(this).slider("value");
var obje = {};
obje[id] = val;
$.extend(question_data, obje);
});
// save data
block.data[block.trial_idx] = $.extend({},{"trial_type": "likert", "trial_index": block.trial_idx, "rt": response_time}, question_data, trial.data);
display_element.html('');
// next trial
block.next();
});
startTime = (new Date()).getTime();
}
return plugin;
})();
})(jQuery);