代码<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
<script type="text/javascript">
var y = 5;
if(y == "5"){
document.write("== '5' True <br/>");
}
else{
document.write("== '5' False <br/>");
}
if(y == 5){
document.write("== 5 数字 is True <br/>");
}
else{
document.write("== 5 数字 False <br/>");
}
if( y === 5){
document.write("=== 数字5 is True <br/>");
}
else{
document.write("=== 数字5 False <br/>");
}
if(y === "5"){
document.write("=== 5 is True <br/>");
}
else{
document.write("=== 5 is False<br/>");
}
</script>
</body>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
<script type="text/javascript">
var y = 5;
if(y == "5"){
document.write("== '5' True <br/>");
}
else{
document.write("== '5' False <br/>");
}
if(y == 5){
document.write("== 5 数字 is True <br/>");
}
else{
document.write("== 5 数字 False <br/>");
}
if( y === 5){
document.write("=== 数字5 is True <br/>");
}
else{
document.write("=== 数字5 False <br/>");
}
if(y === "5"){
document.write("=== 5 is True <br/>");
}
else{
document.write("=== 5 is False<br/>");
}
</script>
</body>
<html>
从以上代码可以看出，等于（==）的情况下 只要值相同就返回True。
而全等（===）的时候需要值和类型都要匹配才能返回True，
