如何检查div在JavaScript中是否具有特定值

Question

I want to know how I can let the JavaScript react when the div has a certain value.

<div id="background">
<div id="value">1</div>
</div>
<script>
var text = document.getElementById("value");
if (text = "0") {
    document.getElementById("background").style.backgroundColor="red";
}
</script>

If the value div has 0, I want the background color to be red of the div called background. If the value div has a other value, it should do nothing. This is what I've come up to. But it don't work. Even if I put another value in the value div, the red background still shows. Except when I emptied the value div, then ofcourse you will see nothing.

Answer 1

var text = document.getElementById("value").innerHTML;
if (text == "0") {
    ...

Answer 2

The comparison operators in JavaScript are == and === , not = (that one is always assignment ). So:

if (text == "0") {

or

if (text === "0") {

You're also not getting the text correctly:

var text = document.getElementById("value");

That gives you the element , not its contents. For contents, use innerHTML .

var text = document.getElementById("value").innerHTML;
// Here -----------------------------------^

Answer 3

<div id="background">
<div id="value">1</div>
</div>
<script>
var text = document.getElementById("value").innerHTML;
if (text == "0") {
    document.getElementById("background").style.backgroundColor="red";
}
</script>

FIDDLE

Answer 4

if you want to use jquery:

if($("#value").html() == "0") {
    $("#background").css("background-color", "red");
}