Javascript implements image upload front page_javascript skills
This article mainly implements image uploading to the front page through code analysis and javascript. No more nonsense, just paste the code directly.
Code example one:
<script>
//检查图片的格式是否正确,同时实现预览
function setImagePreview(obj, localImagId, imgObjPreview) {
var array = new Array('gif', 'jpeg', 'png', 'jpg', 'bmp'); //可以上传的文件类型
if (obj.value == '') {
$.messager.alert("提示", "让选择要上传的图片!");
flag = false;
return false;
}
else {
var fileContentType = obj.value.match(/^(.*)(\.)(.{1,8})$/)[3]; //这个文件类型正则很有用
////布尔型变量
var isExists = false;
var objValue = obj.value;
try {
//对于IE判断要上传的文件的大小
var fso = new ActiveXObject("Scripting.FileSystemObject");
fileLenth = parseInt(fso.getFile(objValue).size);
} catch (e) {
try {
//对于非IE获得要上传文件的大小
fileLenth = parseInt(obj.files[0].size);
} catch (e) {
flag = false;
return false;
}
}
//循环判断图片的格式是否正确
for (var i in array) {
if (fileContentType.toLowerCase() == array[i].toLowerCase()) {
//图片格式正确之后，根据浏览器的不同设置图片的大小
if (obj.files && obj.files[0]) {
//火狐下，直接设img属性
imgObjPreview.style.display = 'block';
imgObjPreview.style.width = '180px';
imgObjPreview.style.height = '200px';
//火狐7以上版本不能用上面的getAsDataURL()方式获取，需要一下方式
imgObjPreview.src = window.URL.createObjectURL(obj.files[0]);
if (fileLenth > 102400) {
$.messager.alert("提示", "请选择小于100k的图片!");
flag = false;
return false;
}
}
else {
//IE下，使用滤镜
obj.select();
var imgSrc = document.selection.createRange().text;
//必须设置初始大小
localImagId.style.width = "180px";
localImagId.style.height = "200px";
//图片异常的捕捉，防止用户修改后缀来伪造图片
try {
localImagId.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)";
localImagId.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = imgSrc;
}
catch (e) {
$.messager.alert("提示", "您上传的图片格式不正确，请重新选择!");
flag = false;
return false;
}
imgObjPreview.style.display = 'none';
document.selection.empty();
}
isExists = true;
flag = true;
return true;
}
}
if (isExists == false) {
$.messager.alert("提示", "上传图片类型不正确!");
flag = false;
return false;
}
flag = false;
return false;
}
}
</script>
<tr class="detailInfo">
<td align="right">
上传照片:
</td>
<td align="left" >
<input type="file" id="idFile" name="idFile" width="150px" runat="server" onchange="javascript:setImagePreview(this,localImag,preview);" />
</td>
</tr>
<tr class="detailInfo">
<td align="right">
预 览:
</td>
<td>
<div id="localImag">
<img id="preview" alt="预览图片" src="../img/userphoto.jpg" style="width: 150px; height: 170px;" />
</div>
</td>
</tr>Code example two:
<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<title>ImageDialog Examples</title>
<link rel="stylesheet" href="../themes/default/default.css" />
<script src="../kindeditor.js"></script>
<script src="../lang/zh_CN.js"></script>
<script>
KindEditor.ready(function(K) {
var editor = K.editor({
allowFileManager : true
});
K('#image1').click(function() {
editor.loadPlugin('image', function() {
editor.plugin.imageDialog({
imageUrl : K('#url1').val(),
clickFn : function(url, title, width, height, border, align) {
K('#url1').val(url);
editor.hideDialog();
}
});
});
});
K('#image2').click(function() {
editor.loadPlugin('image', function() {
editor.plugin.imageDialog({
showLocal : false,
imageUrl : K('#url2').val(),
clickFn : function(url, title, width, height, border, align) {
K('#url2').val(url);
editor.hideDialog();
}
});
});
});
K('#image3').click(function() {
editor.loadPlugin('image', function() {
editor.plugin.imageDialog({
showRemote : false,
imageUrl : K('#url3').val(),
clickFn : function(url, title, width, height, border, align) {
K('#url3').val(url);
editor.hideDialog();
}
});
});
});
});
</script>
</head>
<body>
<p><input type="text" id="url1" value="" /> <input type="button" id="image1" value="选择图片" />（网络图片 + 本地上传）</p>
<p><input type="text" id="url2" value="" /> <input type="button" id="image2" value="选择图片" />（网络图片）</p>
<p><input type="text" id="url3" value="" /> <input type="button" id="image3" value="选择图片" />（本地上传）</p>
</body>
</html>Load this js when you click to select an image. Then copy imageDialog and search for it in image.js, and you will find something similar to this. You should understand at this time, upload_json.jsp sets url, title, width, height, order, align, and the front desk can be used.
The above is the entire content of this article's implementation of the image upload front-end page using JavaScript. I hope you all like it.
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