dom-events | 易学教程

How to set cursor to input box in Javascript?

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问题 document.getElementById(frmObj.id).value=""; document.getElementById(frmObj.id).autofocus; document.getElementById("errorMsg").innerHTML = "Only numeric value is allowed"; In the above code the value of the form object is perfectly setting to "" but there is no cursor in the text box. I want a cursor to be there. focus() only focuses that input box but does not actually set the cursor. 回答1: In JavaScript first focus on the control and then select the control to display the cursor on texbox...

How to add a horizontal line at a specific point in chart.js when hovering?

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问题 I want to be able to add multiple points as a reference place where I can show the horizontal line. Here is an image of what I'm trying to achieve: I want to also make it so that when you don't hover over a point its opacity gets reduced and when you hover over it the opacity is normal. I'm also not sure how to add the square and make the square bigger when hovered hover and it adds the 'wow' text. I appreciate any help. 回答1: You can use chart.js annotations plugin to draw horizontal lines at

Is it possible to trigger the onbeforeunload event programmatically?

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问题 I'm currently using the jquery-form-observe plugin which uses onbeforeunload to prompt the user about "unsaved" changes. But I have a scenario where I need to trigger this on a button click: the button click ultimately leads to the page changing, but I want to prompt the user before they start the process that the button click kicks off... So is there a way to trigger onbeforeunload through jQuery or otherwise? 回答1: I don't know if there is a direct way to do this, but you could always

GWT Custom Event Handler

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问题 Can someone give me an example of creating a custom set of an Event and a Handler. Say you have a Person object that you want your widgets to know if it got updated. You create a HandlerManager and now you have to create an Event and a Handler. How would you define those classes so that you can subscribe and fire events? Most of the Events are DOM based, while I want to create some custom events and handlers that I can fire outside of any browser-based event. 回答1: Here's a pretty

How to execute <script> code in a javascript append

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问题 I'm working with a plugin that is only Javascript. I need to have it dynamically create a DIV element with an advertisement in it. I can't figure out why this doesn't work: $(this).append('<div class="overlay-background">Advertisement <script type="text-javascript"> GA_googleFillSlot("blog_landing_right_rectangle_300x250"); </script>' It results in the element created with "Hello World" but it does not execute the GA-googleFillSlot function. 回答1: appending HTML into the DOM does not cause the

Show/hide div if checkbox selected

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问题 I need a page with checkboxes and visible div if at minimum 1 is checked. Here I got page that if i check checkbox, the div will show. It's okay and works correctly. When I check 3 checkboxes and uncheck 1, the div is missing, when i check some box again, the div will show - it isn't correct. How do I need modify the script to show all time the div, if at minimum 1 checkbox is checked, without this "jumping"? <html> <head> <title>CB Hide/Show</title> <script type="text/javascript"> <!--

How to check whether a Button is clicked by using JavaScript

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问题 Is there a simple way to do something along these lines: JavaScript: if(document.getElementById('button').clicked == true) { alert("button was clicked"); } HTML: <input id="button" type="submit" name="button" value="enter"/> 回答1: You can add a click event handler for this: document.getElementById('button').onclick = function() { alert("button was clicked"); }; This will alert when it's clicked, if you want to track it for later, just set a variable to true in that function instead of

event.clipboardData.setData in copy event

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问题 I have looked at many posts but could not find a clear current answer to the following two questions as it seems standards and browser support has been constantly changing. Is it a legal operation according to the standard to change the clipboard with event.clipboardData.setData inside a 'copy' event handler? Do latest versions of Chrome/FF/Safari/IE/Chrome iOS/Android/iPhones support this correctly? 回答1: Clipboard APIs were indeed in active development as of 2016, but things have stabilized

Native JS equivalent to jQuery delegation

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问题 What is the native implementation for event delegation on dynamically created dom elements? I tried looking at the jQuery source but I can't follow the .on method. Note: Currently I attach the event handlers after the dom elements are created, which seems pretty standard but I like the way jQuery .on handles dynamically created elements events with this syntax $( document ).on( "click", ".selector", handler ); . 回答1: What happens is basically this: // $(document).on("click", <selector>,

How to tell which row number is clicked in a table?

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问题 I have a table like the following: <table> <tr> <td>1</td><td>1</td><td>1</td> </tr> <tr> <td>2</td><td>2</td><td>2</td> </tr> <tr> <td>3</td><td>3</td><td>3</td> </tr> </table> When a user clicks on the table, how can I get the index of this row ( tr element)? For example, when I click on the first tr (with 1 s in the above table), it should pick it up and return 1 . 回答1: This would get you the index of the clicked row, starting with one: $('#thetable').find('tr').click( function(){ alert(