onclick事件触发时调用的函数中的Javascript开关语句

Question

My HTML is this:

 <h3>Please enter your discount code</h3>
    <input type="text" name="discountCode" id="discountCode">
    <div id="message"></div>
    <button id="myButton"  onclick="myFunction()">Click Me</button>

When I click the button, I want the call to myFunction() fire on the event.

My JavaScript is this:

 function myFunction(){
    var discount;
    var discount = document.getElementById("discountCode").innerHTML;
    switch(discount){
        case "SAVE10":
        document.getElementById("message").innerHTML = "you are saving 10% on this order.";
        break;

        case "SAVE15":
        document.getElementById("message").innerHTML = "you are saving 15% on this order.";
        break;

        default:
        document.getElementById("message").innerHTML = "please enter a valid discount code.";
        break;
    }
}

I want to output the messages to the div element of "message". When I run this code and enter a discount code, the only line that outputs to the message div is the default line:

please enter a valid discount code.

Can anyone steer me in the right direction.

Thanks!

Answer 1

Use .value instead of .innerHTML to get value from input tag.

Check below:

 function myFunction() { var discount = document.getElementById("discountCode").value; switch (discount) { case "SAVE10": document.getElementById("message").innerHTML = "you are saving 10% on this order."; break; case "SAVE15": document.getElementById("message").innerHTML = "you are saving 15% on this order."; break; default: document.getElementById("message").innerHTML = "please enter a valid discount code."; break; } } 

 <h3>Please enter your discount code</h3> <input type="text" name="discountCode" id="discountCode"> <div id="message"></div> <button id="myButton" onclick="myFunction()">Click Me</button> 

Also removed var discount you declared twice. That was not required.

Read this for more information : https://www.w3schools.com/jsref/prop_text_value.asp