detect

问题 How can I detect when a removable disk drive is (dis)connected to the system? How to get the mount path (for Linux) and the drive letter (for windows)? EDIT: Is there a way to detect the currently connected devices? 回答1: For Windows, the API RegisterDeviceNotification will let you know when a USB device is added. The information about the volume is given in the DEV_BROADCAST_VOLUME structure. The dbcv_unitmask gives the drive letter. 回答2: You can get the change notifications (for drive added

问题 I know that Ubuntu (and Fedora) uses Upstart istead of the classical System V init daemon (SysVinit). I would like to know how to detect when a USB-drive has been inserted, mount it and copy some files to it. I would like Upstart to call my own script for this. If it is possible I would like Upstart to call the script for a specific USB-drive, so that I would get normal functionality for every USB-drive except my "instant backup" USB-drive. If Upstart could send the USB-drive identification

问题 I have a doodle application that saves an html5 canvas to an image in s3. I want to avoid saving blank (totally transparent) pngs if the user accidentally clicks "save" without having drawn anything. I found that even for a blank canvas the toDataURL() is never an empty string, but huge dump of data. This string appears to always remain the same value if no data is added to the canvas. So one way of detecting an empty canvas is to compare the submitted canvas data to this empty canvas data

问题 I have a doodle application that saves an html5 canvas to an image in s3. I want to avoid saving blank (totally transparent) pngs if the user accidentally clicks "save" without having drawn anything. I found that even for a blank canvas the toDataURL() is never an empty string, but huge dump of data. This string appears to always remain the same value if no data is added to the canvas. So one way of detecting an empty canvas is to compare the submitted canvas data to this empty canvas data

问题 I have a doodle application that saves an html5 canvas to an image in s3. I want to avoid saving blank (totally transparent) pngs if the user accidentally clicks "save" without having drawn anything. I found that even for a blank canvas the toDataURL() is never an empty string, but huge dump of data. This string appears to always remain the same value if no data is added to the canvas. So one way of detecting an empty canvas is to compare the submitted canvas data to this empty canvas data

问题 Is it possible to replace javascript w/ HTML if JavaScript is not enabled on the user's browser? I know I can use <noscript>this displays in place of javascript</noscript> That works fine, but it still runs the javascript. In theory I would want this: if javascript is enabled run javascript if javascript is not enabled don't run javascript and give alternative method I am using this jQuery plugin: http://malsup.com/jquery/cycle/int2.html When I disable javascript on safari, it displays all

问题 Is it possible to replace javascript w/ HTML if JavaScript is not enabled on the user's browser? I know I can use <noscript>this displays in place of javascript</noscript> That works fine, but it still runs the javascript. In theory I would want this: if javascript is enabled run javascript if javascript is not enabled don't run javascript and give alternative method I am using this jQuery plugin: http://malsup.com/jquery/cycle/int2.html When I disable javascript on safari, it displays all

问题 Select makes sense. But can someone explain .detect to me? I don't understand these data. >> [1,2,3,4,5,6,7].detect { |x| x.between?(3,4) } => 3 >> [1,2,3,4,5,6,7].detect { |x| x.between?(3,6) } => 3 >> [1,2,3,4,5,6,7].detect { |x| x.between?(3,7) } => 3 >> [1,2,3,4,5,6,7].detect { |x| x.between?(2,7) } => 2 >> [1,2,3,4,5,6,7].detect { |x| x.between?(1,7) } => 1 >> [1,2,3,4,5,6,7].detect { |x| x.between?(6,7) } => 6 >> [1,2,3,4,5,6,7].select { |x| x.between?(6,7) } => [6, 7] >> [1,2,3,4,5,6,7

问题 Select makes sense. But can someone explain .detect to me? I don't understand these data. >> [1,2,3,4,5,6,7].detect { |x| x.between?(3,4) } => 3 >> [1,2,3,4,5,6,7].detect { |x| x.between?(3,6) } => 3 >> [1,2,3,4,5,6,7].detect { |x| x.between?(3,7) } => 3 >> [1,2,3,4,5,6,7].detect { |x| x.between?(2,7) } => 2 >> [1,2,3,4,5,6,7].detect { |x| x.between?(1,7) } => 1 >> [1,2,3,4,5,6,7].detect { |x| x.between?(6,7) } => 6 >> [1,2,3,4,5,6,7].select { |x| x.between?(6,7) } => [6, 7] >> [1,2,3,4,5,6,7

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 7 years ago . im making a website (wordpress multisite) which is supported by 2 languages for users, there 2 methods we will use it one: -Detect