如何在条件下检查几个局部变量

至少,您可以将验证规则分解为自己的功能:

function IsValid(x)
{
    return (x != undefined && x != "");
}

var x = "";
var y = "";
var z = "";
//...

//...variables get set

if(IsValid(x)) doSomething();
if(IsValid(y)) doSomething();
if(IsValid(z)) doSomething();

除了joel所说的你还可以做以下事情:

function doOnValid(x, func){
 if(x != undefined && x != "") func();
}

然后你可以这样做:

doOnValid(x, doSomething);
doOnValid(y, doSomethingElse);
doOnvalid(z, function() { /*Yay lambda function*/ });