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+# JavaScript 蜘蛛
+
+如何使用JavaScript编写蜘蛛，以便从目标网站自动下载一些svg图像！
+
+
+https://gist.github.com/xgqfrms-GitHub/0bf82ff06037a0d1776c9f30033cbfd1
+
+
+
+http://www.cnblogs.com/post/readauth?url=/xgqfrms/p/6942147.html
+
+
+
+https://rollbar.com/docs/
+
+
+```js
+
+const links = document.querySelectorAll(`ul.image-list a`);
+
+console.log(getComputedStyle(links[0], ':before').getPropertyValue('background-image'));
+// url("https://rollbar.com/assets/shared/logos/ruby-icon.svg")
+
+let img = getComputedStyle(links[0], '::before').getPropertyValue('background-image');
+// url("https://rollbar.com/assets/shared/logos/ruby-icon.svg")
+
+let newImage= img.replace(/(url\(")|("\))/g,'');
+// "https://rollbar.com/assets/shared/logos/ruby-icon.svg"
+
+console.log(newImage);
+// https://rollbar.com/assets/shared/logos/ruby-icon.svg
+
+
+
+
+/*
+add new key to object javascript
+
+
+https://stackoverflow.com/questions/1168807/how-can-i-add-a-key-value-pair-to-a-javascript-object
+*/
+
+
+
+
+
+
+
+
+var a = $("<a>")
+    .attr("href", "http://i.stack.imgur.com/L8rHf.png")
+    .attr("download", "img.png")
+    .appendTo("body");
+
+a[0].click();
+
+a.remove();
+```
+
+
+```js
+const links = document.querySelectorAll(`ul.image-list a`);
+
+let svg_name_arr = [];
+let svg_url_obj = {};
+
+for (let i = 0; i < links.length; i++) {
+    if (links[i].getAttribute('class')) {
+        let x = links[i].getAttribute('class');
+        let y = links[i].setAttribute('download', `${i}-${x}`.svg)
+        svg_name_arr.push(x);
+        let img = getComputedStyle(links[i], '::before').getPropertyValue('background-image');
+        let newImage = img.replace(/(url\(")|("\))/g,'');
+        svg_url_obj[i] = newImage;
+    }
+}
+
+console.log(`svg_name_arr = \n`, svg_name_arr);
+
+console.log(`svg_url_obj = \n`, svg_url_obj);
+
+```
+
+
+
+
+
+
+
+
+
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+
+
+