Using Javascript to compare two input numbers in HTML?

Question

I am using Notepad++ to create a simple web page where a user types in two numbers into a text box, and then presses a button. When they press the button something comes up

Answer 1

Html is a string, not a value. You need to parse it in someway.

EDIT:

The problem seems to be grabbing the values, change it to getElementById and it works fine:

http://jsfiddle.net/fHtZU/10/

HTML

<h1>Assignment 10</h1>

<div id="container">
    <div class="Num">
    <form>
<label class="label1">Enter Value 1:</label>
<input type="text" id="First_num" name="First_num" />
<label class="label1">Enter Value 2:</label>
<input type="text" id="last_num" name="last_num" />
<br/>
<input type="button" id="clickme" value="Which number is greater?" onclick="greaterNum()" />
</form>

js

function greaterNum(){
    var value1;
    var value2;
    value1 = document.getElementById("First_num").value;
    value2 = document.getElementById("last_num").value;
    if (value1 > value2){
        alert(value1 - value2);
        document.body.style.background = "orange";
    }

}

Answer 2

Convert to floats.

value1 = parseFloat(document.First_num.value);
value2 = parseFloat(document.last_num.value);

Answer 3

Values from inputs are retrieved as strings, you need to convert it to number. Try this:

value1 = +document.First_num.value;
value2 = +document.last_num.value;

Also, try to be consistent when naming your input, why caps for one and lowercase for the other?

Answer 4

You may need to use:

value1 = document.getElementById("First_num").value;

However, this only works if you assign the elements id attributes:

<input type="text" id="First_num" name="First_num" value=" " />

Otherwise, use the getElementsByName.

Hope this helps!!