In-depth exploration of the principles and techniques of jQuery iteration

jQuery is a widely used JavaScript library that simplifies processing HTML documents, handling events, performing animations, and more. When using jQuery, it is often necessary to traverse a collection of elements, which involves the principles and techniques of iteration. This article will delve into the principles of jQuery iteration and some common techniques, and use specific code examples to allow readers to better understand and master this knowledge.

1. The principle of iteration

In jQuery, the each() method is often used for iteration operations. The each() method is used to traverse all elements in a jQuery object collection and execute the specified callback function for each element. The basic syntax is as follows:

$(selector).each(function(index, element){
    // 这里是回调函数的执行逻辑
});

In the above code, $(selector) is used to select the specified set of elements, and the each() method will Each element in the collection executes the callback function in turn. index in the callback function represents the index of the currently traversed element in the collection, and element represents the currently traversed element itself.

2. Iteration techniques

1. Traverse elements and change their styles:

// 遍历所有class为item的元素，改变它们的背景颜色
$(".item").each(function(){
    $(this).css("background-color", "red");
});

2. Traverse form elements and get values:

// 遍历所有input元素，获取它们的value值
$("input").each(function(){
    console.log($(this).val());
});

3. Filter the elements before iterating:

// 遍历所有class为item的元素中，过滤出display为block的元素并改变样式
$(".item").filter(function(){
    return $(this).css("display") === "block";
}).each(function(){
    $(this).css("font-weight", "bold");
});

3. Summary

Through the introduction of this article, readers can have a deeper understanding of jQuery iteration Principles and Techniques. Iteration is one of the commonly used operations in jQuery. Proficient in iteration skills can make the code more concise and efficient. I hope readers can flexibly use jQuery's iteration function in actual projects to improve development efficiency and code quality.

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