在php 中
$a = '0';
$b = (bool)$a;
var_dump($a);//输出false
在js中官方说明:
Note:If the value parameter is omitted, or is 0, -0, null, , false, undefined, or NaN, the object is set to false.
Otherwise it is set to true (even with the string false)!
测试:
<script type="text/javascript">
var a='0';
if(a){
alert(1);
}else{
alert(0);
}
</script> 值为true。