CSS fill pattern

To create the fill pattern image, check out the following website:

     http://www.patternify.com/

/*dots*/

.inactive_cell2 {
    background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAQAAAAECAYAAACp8Z5+AAAAEklEQVQImWNgYGD4z0AswK4SAFXuAf8EPy+xAAAAAElFTkSuQmCC");
    background-repeat: repeat;
}

To create strips without using any image data,

    https://css-tricks.com/stripes-css/

/*stripes*/
.inactive_cell {   
    background: repeating-linear-gradient( 48deg, #fefefe, #e0e0e1 5px, #eaeaea 5px, #eaeaea 10px );
}

Simple pie chart & doughnut chart with SVG + CSS

You can draw a simple pie chart & doughnut chart with SVG + CSS. This is quite simple and straight forward. But the limitation is that it is able to show 2 sections only.

To change the value of the section, look for stroke-dasharray and change the first value.

.pie2 {

        fill: yellow;

        stroke: green;

        /* max=50 (radius x 2) */

        stroke-width: 50;

        /* 158 = (radius x 2) x 3.142 = 25 x 2 x 3.142 */

        stroke-dasharray: 40 158;

    }

    .chart2 {

        background-color: yellow;

        border-radius: 50%;

        -webkit-transform: rotate(-90deg);

                transform: rotate(-90deg);

    }

    <svg width="100" height="100" class="chart2">    

        <circle r="25" cx="50" cy="50" class="pie2"/>  

    </svg>

To draw a doughnut chart,  

    .doghnut {

        fill: yellow;

        stroke: green;

        stroke-width: 20;

        stroke-dasharray: 180 251;

    }

    .doghnut_chart {

        background-color: yellow;

        border-radius: 50%;

        -webkit-transform: rotate(-90deg);

                transform: rotate(-90deg);

    }

    <svg width="100" height="100" class="doghnut_chart">    

        <circle r="40" cx="50" cy="50" class="doghnut"/>  

    </svg>

Javascript that prevents double click on submit button

This is what happening:

• The user loves "double clicking" on any button even though single click will trigger the action.
• The Internet connection slows down and the user thought that he did not click on the correct button. So, he decided to click it again even though the waiting time is lesser than 1 second (?!).

To solve this, you need the following JavaScript to ensure that the submit is working with single click only. Note: you may adjust the value of "500" (ms) to whatever value that you want.

var _prev_save_click_ts = null;

function beforeSubmit() {

    if (_prev_save_click_ts != null) {
        var ts = new Date();

        if (ts - _prev_save_click_ts < 500) {
            // user is double clicking.
            return false;
        }
    }

    _prev_save_click_ts = new Date();
    return true;
}

Easiest way to search without using loop

If you have two sets of data and one set is referencing the other set, you will need to do a "double loop" to iterating through the data. But, there is a way to eliminate one loop and shorten the code.

For example, set 1 is the list of employees and set 2 is the list of working shift.

If you are using FOR loop, your codes will look similar to the following:

var employees = [];
employees.push({name: 'Mike', shift_id:'A'});
employees.push({name: 'Micky', shift_id:'B'});
employees.push({name: 'Mini', shift_id:'C'});

var shifts = [];
shifts.push({id: 'A', start_time: '08:00', end_time: '17:00'});
shifts.push({id: 'B', start_time: '09:00', end_time: '18:00'});

var s;

for (var i = 0; i < employees.length; i++) {
    s = null;

    // look for the shift:
    for (var j = 0; j < shifts.length; j++) {
         if (shifts[j].id == employees[i].shift_id) {
            s = shifts[j];
            break;
        }
    }

     if (s != null){
           console.log(employees[i].name, s.start_time);
     } else {
           console.log(employees[i].name, 'Cannot find the shift record');
     }
}

The JavaScript object is a key value collection:

   o = {};
   o['a'] = 'Apple';
   o['b'] = 'Banana';

And you can access the value:

   console.log(o['b']);

Below is the code that uses the key value collection to store the shift information and it will save us from writing one FOR loop.

var employees = [];
employees.push({name: 'Mike', shift_id:'A'});
employees.push({name: 'Micky', shift_id:'B'});
employees.push({name: 'Mini', shift_id:'C'});

var shifts = {};
shifts['A'] = {id: 'A', start_time: '08:00', end_time: '17:00'};
shifts['B'] = {id: 'B', start_time: '09:00', end_time: '18:00'};

var s;

for (var i = 0; i < employees.length; i++) {
    s = null;

    // look for the shift:
    if (shifts.hasOwnProperty(employees[i].shift_id)) {
            s = shifts[employees[i].shift_id];
           console.log(employees[i].name, s.start_time);
     } else {
           console.log(employees[i].name, 'Cannot find the shift record');
     }
}

Printing HTML with JavaScript

You want to allow the user from printing current page directly to the printer and here is the recipe:


1. A print button that calls your print function (written in JavaScript).

2. In your print function, you need to do the following thing:

2.1. Inject a hidden iFrame.

2.2. Set the "src" to the page that you have to print. If you are developing a POS (Point of Sales), you may specify the URL of the receipt page to the "src" together with the  receipt number in the query string. For example,

<iframe id="receipt-frame" style="display:none;" src="myReceipt.aspx?refno=123456"/>

Note: the page that you call should return the contents to be printed out. You have two choices to merge the data into the receipt format: (1) do everything at the server side (2) execute client side JavaScript upon page loaded.

2.3. Once you have the content to be printed, you need to call the following function (upon page loaded). This function will send the content to the printer.

  window.onafterprint = function() {
      window.parent.myPrintJobCompleted();
  }

  window.print();

In case you want to inform the parent page that the user has printed the content, you must handle the window.onafterprint event. In the example above, it executes the function myPrintJobCompleted (this function will load with the main page).