JavaScript中的全局变量在函数内改变

Question

嗨我想改变一个函数内的全局变量，但它似乎并没有这样工作。这是我的JS：

var currentImg = 0; 
var totalImg = 0; 
var stored_year = 0; 
var newYear = 0; //the variable i want to edit 

$("a.work").click(function(){ 
    var newYear = $(this).html(); // how I want it to be edited 
    console.log(newYear); 
}); 

$("#next-button").click(function() { 
    if (currentImg == totalImg) { 
     currentImg = 0; 
    } 
    else { 
     currentImg++; 
    } 
    changeImg(); 
}); 

$("#previous-button").click(function() { 
    if (currentImg == 0) { 
     currentImg = totalImg; 
    } 
    else { 
     currentImg--; 
    } 
    changeImg(); 
}); 

function changeImg(galleryYear) { 

    if (galleryYear === stored_year) { 


     $("#gallery-image").html("<img src='" + galleryYear.x_src[currentImg] + "'>"); 
     $("#gallery-title").html(galleryYear.x_title[currentImg]); 
     $("#gallery-medium").html(galleryYear.x_medium[currentImg]); 
     $("#gallery-size").html(galleryYear.x_size[currentImg]); 
     $("#gallery-date").html(galleryYear.x_date[currentImg]); 

     var userCurrent = currentImg + 1; 
     var userTotal = galleryYear.x_id.length; 

     $("#current-post").html(userCurrent); 
     $("#post-total").html(userTotal); 

     var galWidth = $("#gallery-image" > "img").width(); 
     $("#gallery").width(galWidth); 

    } 
    else { 

     currentImg = 0; 
     $("#gallery-image").html("<img src='" + galleryYear.x_src[currentImg] + "'>"); 
     $("#gallery-title").html(galleryYear.x_title[currentImg]); 
     $("#gallery-medium").html(galleryYear.x_medium[currentImg]); 
     $("#gallery-size").html(galleryYear.x_size[currentImg]); 
     $("#gallery-date").html(galleryYear.x_date[currentImg]); 

     var userCurrent = currentImg + 1; 
     var userTotal = galleryYear.x_id.length; 

     $("#current-post").html(userCurrent); 
     $("#post-total").html(userTotal); 

     var galWidth = $("#gallery-image" > "img").width(); 
     $("#gallery").width(galWidth); 

     $("#gallery-type").html('<img id="gallery-switch" alt="Kyle Breitenbach Art Gallery Icon" src="images/gallery-icon.png" onClick="gallerySwitch('+window.newYear+')">'); 

     stored_year = galleryYear; 
    } 

} 

t = 100; 
d = 50; 

function gallerySwitch(newYear){ 
    $("#gallery-control-bar").fadeOut(t); 
    $("#gallery-image").fadeOut(t); 
    $("#info").fadeOut(t); 
    $(".gallery-viewer").fadeOut(t); 
    $('div.'+newYear).delay(t+d).fadeIn(t); // still not returning a number 
}             // other than 0. 

function switchBack(){ 
    currentImg = parseInt($(this).attr('id')); 
    alert(currentImg); 

    $(".gallery-viewer").fadeOut(t); 
    $("#gallery-control-bar").delay(t+d).fadeIn(t); 
    $("#gallery-image").delay(t+d).fadeIn(t); 
    $("#info").delay(t+d).fadeIn(t); 
} 

var navB = 0; 

$("#mobileNav").click(function() { 
    if (navB == 0) { 
     $("#mobileMenu").fadeIn(t); 
     navB++; 
    } 
    else { 
     $("#mobileMenu").fadeOut(t); 
     navB--; 
    } 
}); 



$(document).ready(function() { 
    changeImg(galleryYear); 
}); 

如何使变量从一个函数内全局？

Answer 1

您可以有多个变量名称相同，并且会互相影响。当您想要使用现有变量时，请勿添加var。

$("a.work").click(function(){ 
    newYear = $(this).html(); 
    console.log(newYear); 
}); 

Answer 2

您已经在函数中添加了var newYear =，这将创建一个本地版本。让它只是NEWYEAR =

Answer 3

就不会再在该方法中，如果你想NEWYEAR采取$（“a.work”）值声明NEWYEAR：

$("a.work").click(function(){ 
    newYear = $(this).html(); // how I want it to be edited 
    console.log(newYear); 
}); 

Answer 4

如果您创建具有相同的局部变量命名为全局它将优先：

var newYear = 0; 
$("a.work").click(function(){ 
    var newYear = $(this).html(); // This is not your global newYear 
} 

你必须使用完全合格的名称：

var newYear = 0; 
$("a.work").click(function(){ 
    var newYear = $(this).html(); // This is not your global newYear 
    window.newYear = 'This is your global newYear'; 
} 

但是全局变量的代码已经很难维护，没有重名。我建议你使用独特的名字。