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BIT116 : Scripting

Learn about radio buttons in scripting and how to use them in HTML forms. Understand their functionality and how to handle user inputs.

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BIT116 : Scripting

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  1. BIT116: Scripting Radio Buttons

  2. Let’s first review due dates • A2 first revision is due today • A1 revision is (technically) due at the start of next class • I promise that I’ll grade the midterm exam before A1 revision • So you’ll (technically) have an extra day or two to finish A1 • Remember that you can upload your work as many times as you’d like….… just make sure to include a complete copy (ALL FILES) even if you haven’t changed some • A3 is due in 1 week

  3. Today • Quiz • Go over the Midterm Topic List • Radio Buttons • Check boxes

  4. Radio buttons

  5. Radio buttons • Image from: https://en.wikipedia.org/wiki/Radio_button • HTML: • We're NOT going to use id here • (we can't have duplicates id's) • Instead, we're going to give all the individual HTML elements the same name • (name attribute allows for duplicates) • We need to define the text separately • "Cat", "Dog", and "Turtle" in the above image • FILE:radio_buttons_demo.html

  6. What the demo page looks like:

  7. <h2>Radio Buttons</h2> <form> <h3>How much does BIT 116 rock?</h3> <p> <input type="radio"name="enthusiasm"value="High">Totally A Ton!!!!<br/> Text before button <input type="radio" name="enthusiasm" value="SoSo"> It's Ok <!-- since there's no br, there's no line break --> <input type="radio" name="enthusiasm" value="Low">Why, God, why did I sign up for this class?<br/> <input type="button" id="getFeedback" value="Click here for feedback!"> </p> </form> <p id="msgHere">Some Fascinating Text! That I will change! With jQuery!</p> • <input = Start of the button itself. Note that there's no closing tag. This element puts ONLY the button on the page • type="radio" = Tells the browser to put a radio button on the page • name="enthusiasm" = We picked enthusiasm. Pick any valid name you want, but be consistent • value="High"> = Again, pick anything you want (we picked High). Each button needs to have a unique value. For the others we picked SoSoand Low. • Totally A Ton!!!!<br/> = Notice that the text is outside the button and unconnected to it

  8. $("#getFeedback").click( function() { varwhichOne = $('input:radio[name=enthusiasm]:checked').val(); // First, what do we get: // >>> is added so it's clear what the var is, even if it's empty/blank alert(">>>" + whichOne + "<<<"); • $('input = We're going to start by asking for all the 'input elements, and then filtering out the ones we're not interested in • :radio = Ignore (filter out) anything who's type is not radio • (as specified using the type="radio" attribute in the HTML – see previous slide) • [name=enthusiasm] = Amongst the radio buttons, only look at those elements who have a name attribute and that name attribute is 'enthusiasm' • :checked') = Amongst the radio inputs named 'enthusiasm', select the one that is checked (if any) • .val(); = Finally, get the value from that button. The value will be either High, SoSo, or Low (as specified using the value="…"> attribute in the HTML – see previous slide)

  9. $("#getFeedback").click( function() { varwhichOne = $('input:radio[name=enthusiasm]:checked').val(); // First, what do we get: // >>> is added so it's clear what the var is, even if it's empty/blank alert(">>>" + whichOne + "<<<"); • We're going to start off by simply showing the value of the radio button

  10. $("#getFeedback").click( function() { varwhichOne = $('input:radio[name=enthusiasm]:checked').val(); // <snip> - to fit everything on one slide  if( whichOne === undefined ) $("#msgHere").html( "You need to make a choice!"); else if( whichOne === "High" ) $("#msgHere").html( "Great! I'm glad that you're enjoying the course"); else if( whichOne === "SoSo" ) $("#msgHere").html( "That's too bad. What can I do to help?"); else if( whichOne === "Low" ) $("#msgHere").html( "That's definitely too bad! Please talk to the prof to get some help ASAP!! :( :( :("); else $("#msgHere").html( "INTERNAL ERROR: We should never execute this line of code!!"); }); • if( whichOne === undefined ) = check if the user didn't select anything • NOTE: there's no quotes around the undefined !!! • if( whichOne === "High" ) = Otherwise look for the text that we specified in the HTML • else = We shouldn't need this, but it's better to be safe than sorry

  11. Do Exercises • Work on Exercise #1 for the 'radio buttons' section of this lecture

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