Dynamically modify the change of data through button click event

This article aims to solve the problem of dynamically modifying JavaScript variable data through HTML button click events. The article will explain in detail how to implement this functionality correctly, including avoiding common mistakes, using modern JavaScript syntax, and providing clear code examples. By reading this article, you will be able to master the skills to update variable data dynamically through button click events and apply it to your web development project.

In web development, it is often necessary to dynamically update the data on the page based on user interaction. Among them, it is a common requirement to modify the value of a variable through a button click event. This article will explain how to implement this function correctly and avoid some common mistakes.

Variable declaration and scope

First, we need to declare variables to store different datasets. It is recommended to use the const and let keywords instead of var. const is used to declare constants, i.e. variables whose values ​​are not modified, while let is used to declare variables that can be modified. This helps improve the readability and maintainability of the code.

 let chartdata = [];
const eqdata = [['a',2],['b',6],['r',9],['s',8]];
const debdata = [['p',2],['r',6],['r',9],['d',8]];
const hybdata = [['l',2],['k',6],['rr',9],['df',8]];

Event handling function

Next, we need to create an event handler function that will be executed when the button is clicked. In this function, we will update the chartdata variable based on the id of the button we clicked.

 function clicked(){
    const id = event.srcElement.id;
    if (id == 'eqty'){
        chartdata = eqdata;
    } else if (id == "debt"){
        chartdata = debdata;
    } else if (id == "hyb"){
        chartdata = hybdata;
    }
    // Here you can add code to update the chart, for example:
    // updateChart(chartdata);
    console.log(chartdata); // Output updated data};

Notice:

• When comparing strings, be sure to use == or ==, instead of =. = is an assignment operator that assigns the value on the right to the variable on the left. Use == or === to correctly compare whether the values ​​of two strings are equal.
• event.srcElement.id is used to get the id of the element that triggers the event.

HTML Structure

Finally, we need to create the HTML button and bind the onclick event to the clicked function.

 <div class="row" style="margin:auto; padding: 8px 8px 0" id="categories">
  <button id="eqty" class="btn btn-primary" style="'margin:" onclick="clicked()">Equity Chart</button>
  <button id="debt" class="btn btn-primary" style="'margin:" onclick="clicked()">Debt Chart</button>
  <button id="hyb" class="btn btn-primary" style="'margin:" onclick="clicked()">Hybrid Chart</button>
</div>

Complete code example

Combine the above code snippets to get a complete code example:

 <div class="row" style="margin:auto; padding: 8px 8px 0" id="categories">
    <button id="eqty" class="btn btn-primary" style="'margin:" onclick="clicked()">Equity Chart</button>
    <button id="debt" class="btn btn-primary" style="'margin:" onclick="clicked()">Debt Chart</button>
    <button id="hyb" class="btn btn-primary" style="'margin:" onclick="clicked()">Hybrid Chart</button>
</div>

<script>
    let chartdata = [];
    const eqdata = [[&#39;a&#39;,2],[&#39;b&#39;,6],[&#39;r&#39;,9],[&#39;s&#39;,8]];
    const debdata = [[&#39;p&#39;,2],[&#39;r&#39;,6],[&#39;r&#39;,9],[&#39;d&#39;,8]];
    const hybdata = [[&#39;l&#39;,2],[&#39;k&#39;,6],[&#39;rr&#39;,9],[&#39;df&#39;,8]];

    function clicked(){
        const id = event.srcElement.id
        if (id == &#39;eqty&#39;){
            chartdata = eqdata;
        } else if (id == "debt"){
            chartdata = debdata;
        } else if (id == "hyb"){
            chartdata = hybdata;
        }
        console.log(chartdata);
    };
</script>

Summarize

Through this article, we learned how to dynamically modify the data of JavaScript variables through button click events. Key points include:

• Use const and let to declare variables.
• Compare strings correctly.
• Use event.srcElement.id to get the id of the element that triggered the event.
• Update the value of the variable in the event handler.

By mastering these techniques, you can easily implement the ability to update variable data dynamically through button click events and apply it to your web development project.

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