如何使用给定的url检查图像是否存在?

I want to check if an image exists using jquery.

我想检查是否存在使用jquery的图像。

For example how do I check this image exists

例如，如何检查这个图像是否存在

http://www.google.com/images/srpr/nav_logo14.png 

the check must give me a 200 or status ok

这张支票必须给我200英镑的支票

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var imgsrc = $(this).attr('src');
var imgcheck = imgsrc.width;


if (imgcheck==0) {
alert("You have a zero size image");
} else { //do rest of code }

Thanks Jean

谢谢你简

5 个解决方案

#1

Use the error handler like this:

使用错误处理程序如下:

$('#image_id').error(function() {
  alert('Image does not exist !!');
});

If the image cannot be loaded (for example, because it is not present at the supplied URL), the alert is displayed:

如果无法加载图像(例如，因为该图像不在提供的URL中)，则显示警报:

Update:

更新:

I think using:

我认为使用:

$.ajax({url:'somefile.dat',type:'HEAD',error:do_something});

would be enough to check for a 404.

检查404页面就足够了。

More Readings:

更多阅读:

• http://www.jibbering.com/2002/4/httprequest.html
• http://www.jibbering.com/2002/4/httprequest.html
• http://www.ibm.com/developerworks/web/library/wa-ajaxintro3/
• http://www.ibm.com/developerworks/web/library/wa-ajaxintro3/

Update 2:

更新2:

Your code should be like this:

你的代码应该是这样的:

$(this).error(function() {
  alert('Image does not exist !!');
});

No need for these lines and that won't check if the remote file exists anyway:

不需要这些行，也不检查远程文件是否存在:

var imgcheck = imgsrc.width;    

if (imgcheck==0) {
  alert("You have a zero size image");
} else { 
  //execute the rest of code here 
}

#2

$.ajax({
    url:'http://www.example.com/somefile.ext',
    type:'HEAD',
    error: function(){
            //do something depressing
    },
    success: function(){
            //do something cheerful :)
    }
});

from: http://www.ambitionlab.com/how-to-check-if-a-file-exists-using-jquery-2010-01-06

来自:http://www.ambitionlab.com/how -检查-如果-文件-存在使用jquery - 2010 - 01 - 06

#3

if it doesnt exist load default image or handle error

如果它不存在，加载默认图像或处理错误

$('img[id$=imgurl]').load(imgurl, function(response, status, xhr) {
    if (status == "error") 
        $(this).attr('src', 'images/DEFAULT.JPG');
    else
        $(this).attr('src', imgurl);
    });

#4

Use Case

$('#myImg').safeUrl({wanted:"http://example/nature.png",rm:"/myproject/images/anonym.png"});

API :

$.fn.safeUrl=function(args){
  var that=this;
  if($(that).attr('data-safeurl') && $(that).attr('data-safeurl') === 'found'){
        return that;
  }else{
       $.ajax({
    url:args.wanted,
    type:'HEAD',
    error:
        function(){
            $(that).attr('src',args.rm)
        },
    success:
        function(){
             $(that).attr('src',args.wanted)
             $(that).attr('data-safeurl','found');
        }
      });
   }


 return that;
};

---

Note : rm means here risk managment .

注意:rm的意思是风险管理。

---

Another Use Case :

$('#myImg').safeUrl({wanted:"http://example/1.png",rm:"http://example/2.png"})
.safeUrl({wanted:"http://example/2.png",rm:"http://example/3.png"});

• 'http://example/1.png' : if not exist 'http://example/2.png'

  “http://example/1。png':如果不存在'http://example/2.png'

• 'http://example/2.png' : if not exist 'http://example/3.png'

  “http://example/2。png':如果不存在'http://example/3.png'

#5

From here:

从这里开始:

// when the DOM is ready
$(function () {
  var img = new Image();
  // wrap our new image in jQuery, then:
  $(img)
    // once the image has loaded, execute this code
    .load(function () {
      // set the image hidden by default    
      $(this).hide();
      // with the holding div #loader, apply:
      $('#loader')
        // remove the loading class (so no background spinner), 
        .removeClass('loading')
        // then insert our image
        .append(this);
      // fade our image in to create a nice effect
      $(this).fadeIn();
    })
    // if there was an error loading the image, react accordingly
    .error(function () {
      // notify the user that the image could not be loaded
    })
    // *finally*, set the src attribute of the new image to our image
    .attr('src', 'images/headshot.jpg');
});