为什么背景颜色不改成绿色？
var id;
id = setInterval(changeColor, 1000);
function changeColor(){
var elem= $("#target");
var color = elem.css('background-color');
if (color == 'rgb(255,0,0)')
elem.css('background-color','green');
else
elem.css('background-color', 'red');
}
请尝试以下操作:
var id;
id = setInterval(changeColor, 1000);
function changeColor(){
var elem= $("#target");
var color = elem.css('background-color');
if (color == 'rgb(255, 0, 0)')
elem.css('background-color','green');
else
elem.css('background-color', 'red');
}
if语句检查了错误的条件:'rgb(255，0，0）'vs'rgb(255，0，0）'
尝试检查rgba而不是RGB。
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<html>
<head>
<title>Change Color</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script>
function changeColor(){
var elem= $("#target");
var color = elem.css('background-color');
if (color == 'rgba(0, 0, 0, 0)')
elem.css('background-color','green');
else
elem.css('background-color', 'red');
}
$(document).ready(function () {
var id;
id = setInterval(changeColor, 1000);
});
</script>
</head>
<body>
<div id="target">Welcome to JavaScript!!!</div>
<!--.div-row -->
</body>