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Chapter 6
For this cell, we will be coding in HTML and a little JavaScript. First, define a div
element to store our current tweet to be labeled. I've also added some instructions for
using this form. Then, create the #tweet_text div that will store the text of the next
tweet to be labeled. As stated before, we need to create a textbox to be able to capture
key presses. The code is as follows:
Instructions: Click in textbox. Enter a 1 if the tweet is
relevant, enter 0 otherwise.
Tweet:
Don't run the cell just yet!
We create the JavaScript for capturing the key presses. This has to be defined
after creating the form, as the #tweet_text div doesn't exist until the above
code runs. We use the JQuery library (which IPython is already using, so we don't
need to include the JavaScript file) to add a function that is called when key presses
are made on the #capture textbox we defined. However, keep in mind that this is
a %%html cell and not a JavaScript cell, so we need to enclose this JavaScript in the
tags.
We are only interested in key presses if the user presses the 0 or the 1, in which case
the relevant label is added. We can determine which key was pressed by the ASCII
value stored in e.which. If the user presses 0 or 1, we append the label and clear out
the textbox. The code is as follows:
$("input#capture").keypress(function(e) {
if(e.which == 48) {
set_label(0);
$("input#capture").val("");
}else if (e.which == 49){
set_label(1);
$("input#capture").val("");
}
});
All other key presses are ignored.
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