Question

Helo朋友我编写了一个js脚本来找出函数中的值。代码是

function hello(this) {
this.value = 10;
document.write(this);
};


var c = new hello(c);
c();

但我得到这个输出为空白...我知道这取决于函数的调用方式，这里c是这个值。所以输出必须是c。

我想在这里改变new hello(to any string)还是像我一样改变。{/ p>

请帮我解决这个问题并让我纠正......任何帮助都会受到赞赏..谢谢..

Answer 1

嗯，首先你不能使用＆＃34;这个＆＃34;作为javascript中的变量，因为它是一个保留关键字，你最好使用其他东西。其次，如果要将字符串传递给函数，则必须将其括在单引号（＆＃39;）或双引号（＆＃34;）之间。第三，您的函数不返回任何值，因此不需要将其分配给变量。第四，你要在＆＃34; ths＆＃34;对象，但如果你知道我的意思，你就不会返回。那是我的评论。您的代码更正将是：

function hello(ths) {
document.write(ths);
};

hello("your string goes here");

Answer 2

尝试：

/* incoming variable we set when calling our function, currently reads: Hello there! */
var hello = function(incoming) { 
     /* incoming variable being overwritten, now reads: 10 */
     incoming = 10; 
     /* writing 10 to document, overwriting anything already written to document */
     document.write(this); 
};
/* calling your function 'hello' as well as setting incoming variable to: Hello there! */
var a = new hello('Hello there!');

Answer 3

框架结构，扎实。我假设你是在追求这样的事情？

function hello ()
{
    // inside a function (soon to be object) "this" refers to that object
    this.value = 10; // can and must be called by c.value outside of the declared function

    this.sayHello = function( msg )
    {
        this.value = msg; // is equal to c.value (outside of hello), overwrites old value with new message
        document.write( msg );
    }
}

// 'new' prefix types an object, represented by 'c'
var c = new hello;

c.sayHello( 'your message' );
// Your most recent message is stored in c.value

javascript中的空白输出

3 个答案: