Question

SYNTAX错误已修复。 Dreamweaver说我的代码在第52行有错误。我看不出有什么问题？也许这与我的if和else语句不起作用有关。

IF AND ELSE STATEMENTS FIXED。如果我单独测试if和else语句，它们可以正常工作，但是当我运行整个文档时，它们不会运行。有人可以告诉我错误和我的if / else语句是否有效或者是否有其他错误。

<script>
var car1=new Object();
car1.Name="Rusty";
car1.Speed="1px", 40;
car1.Distance=0;

var car2=new Object();
car2.Name="Dusty";
car2.Speed="2px", 40; 
car2.Distance=0;

var car3=new Object();
car3.Name="Crankshaft";
car3.Speed="4px", 40;
car3.Distance=0;

function runRusty(){

setInterval(function(){moveRusty()},40);

    function moveRusty(){car1.Distance=car1.Distance +1
        document.getElementById("rusty").style.marginLeft=car1.Distance + "px" 
        };
};


function runDusty(){

setInterval(function(){moveDusty()},40);

    function moveDusty(){car2.Distance=car2.Distance +1
        document.getElementById("dusty").style.marginLeft=car2.Distance + "px" 
        };
 };


function runCrankshaft(){

setInterval(function(){moveCrank()},40);

    function moveCrank(){car3.Distance=car3.Distance +1
          document.getElementById("crankshaft").style.marginLeft=car3.Distance + "px" 
        };
};


function winLose () {if (document.getElementById("rusty").style.marginLeft="900px"){
                     alert("Winner is Rusty!");
                     clearInterval(runRusty);
                     }

else    if(document.getElementById("dusty").style.marginLeft="900px"){
                    alert("Winner is Dusty!");
                    clearInterval(runDusty);
                    }

                else if(document.getElementById("crankshaft").style.marginLeft="900px"){
                    alert("Winner is Crankshaft!");
                    clearInterval(runCrankshaft);
                    };
                };
</script>

修改

if和else语句现在可以正常工作，因为我更改了全局声明我的函数并稍微改变了它们。代码现在看起来像这样：

    var car1=new Object();
    car1.Name="Rusty";
    car1.Speed=1;
car1.Distance=0;

var car2=new Object();
car2.Name="Dusty";
car2.Speed=2; 
car2.Distance=0;

var car3=new Object();
car3.Name="Crankshaft";
car3.Speed=4;
car3.Distance=0;

var moveRusty;
var moveDusty;
var moveCrankShaft;


function runRusty(){

moveRusty=setInterval(function(){

        car1.Distance=car1.Distance + car1.Speed;
        document.getElementById("rusty").style.marginLeft=car1.Distance + "px";
        winLose();
        },40);
};


function runDusty(){

moveDusty=setInterval(function(){

        car2.Distance=car2.Distance + car2.Speed;
        document.getElementById("dusty").style.marginLeft=car2.Distance + "px"; 
        winLose();
        },40);
};

function runCrankshaft(){

moveCrankShaft=setInterval(function(){

        car3.Distance=car3.Distance + car3.Speed;
        document.getElementById("crankshaft").style.marginLeft=car3.Distance + "px"; 
        winLose();
        },40);
}

function winLose () {

    if (car1.Distance >= 900){
        alert("Winner is Rusty!");
        car1.Distance = 0;
        car1.Speed = 0;
        car2.Distance = 0;
        car2.Speed = 0;
        car3.Distance = 0;
        car3.Speed = 0;



    }

    else 

    if(car2.Distance >= 900){
        alert("Winner is Dusty!");
        car1.Distance = 0;
        car1.Speed = 0;
        car2.Distance = 0;
        car2.Speed = 0;
        car3.Distance = 0;
        car3.Speed = 0;


    }

    else 

    if(car3.Distance >= 900){
        alert("Winner is Crankshaft!");
        car1.Distance = 0;
        car1.Speed = 0;
        car2.Distance = 0;
        car2.Speed = 0;
        car3.Distance = 0;
        car3.Speed = 0;

    }
};

clearInterval(moveRusty);
clearInterval(moveDusty);
clearInterval(moveCrankShaft);

现在一切正常。发生所有警报并重置汽车的位置。但我所有的clearInterval（）都不起作用。我不知道clearInterval（）是否正确使用。我想要做的是重置页面，以便我可以再次运行“游戏”。现在，唯一的方法是刷新页面。我已经仔细检查了我如何声明我的setInterval（）以及我是如何在clearInterval（）中调用它们的，并且尽我所能它是正确的？

Answer 1

您使用clearInterval()错误。您正在向它传递一个函数参数，而它需要一个对象。

// correct usage
var time = setInterval(stuff, 100);
clearInterval(time);

Answer 2

你在别的前面有一个半冒号。 ;这是语法错误，请将其删除。你也有很多奇怪的地方，我建议你不要把它们放在函数声明之后，如果块阻塞if / else块，循环块等等。

Answer 3

如果您想在if语句中测试某些内容是否“相等”，则需要使用==或===而不是=

if (document.getElementById("crankshaft").style.marginLeft = "900px") // WRONG
if (document.getElementById("crankshaft").style.marginLeft == "900px") // RIGHT
if (document.getElementById("crankshaft").style.marginLeft === "900px") // BETTER

阅读以下问题的答案，了解==和===

之间的区别

Difference between == and === in JavaScript

希望这有帮助

clearInterval（）不起作用

3 个答案: