jquery replace placeholder

In front-end development, jQuery is often used to implement various operations. Among them, replacing placeholders is also a common requirement. For example, in a string, there are some placeholders that need to be replaced according to different data. At this time, you need to use jQuery to replace placeholders.

1. Definition of placeholder

Placeholder refers to a special character used to place a place in a string. Usually the form of placeholder is {}, where {} is the left and right brackets. For a string containing placeholders, the position and number of placeholders need to be defined first, and then replaced based on the incoming data. For example, in the following string, {} is the placeholder:

"My name is {}, I am {} years old this year, and my birthplace is {}."

This string There are three placeholders for name, age, and birthplace.

2. jQuery implements placeholder replacement

In jQuery, you can use some methods to achieve placeholder replacement. The more commonly used methods are replace() and replaceWith(). Both methods can be used to replace parts of a string.

1. replace() method

The replace() method is JavaScript’s own string method, which can be used to replace specified parts of the string. When using the replace() method, you need to specify the part to be replaced and the new content. For example, in the following code, the replace() method is used to replace the placeholder:

var str = "My name is {}, I am {} years old this year, and my birthplace is {}.";
var newData = ["Zhang San", 18, "Beijing"];
for (var i = 0; i < newData.length; i ) {
str = str.replace("{} ", newData[i]);
}

In this example, a string containing placeholders is first defined, and then an array newData is defined to store the data to be replaced. Next, use a for loop to iterate through the array, replacing one element of the array into the placeholder each time. The final result is as follows:

"My name is Zhang San, I am 18 years old this year, and I was born in Beijing."

This method is relatively simple, but if there are many placeholders, it will The replace() method needs to be called multiple times, which is troublesome. Therefore, we can use the simpler method replaceWith().

2. replaceWith() method

The replaceWith() method is a method in jQuery that can be used to replace the content in an element. Similar to the replace() method, you also need to specify the part to be replaced and the new content. However, the replaceWith() method can replace the entire element, including the element's tags and attributes. This method requires a jQuery object as a parameter to represent the content to be replaced.

For placeholder replacement, you can first create a string containing the placeholder. When replacement is needed, convert the string into a jQuery object and use the replaceWith() method to replace it with a new one. content. The code is as follows:

var str = "My name is {}, I am {} years old this year, and my birthplace is {}.";
var newData = ["Zhang San", 18, " Beijing"];

$.each(newData, function(i, val) {
str = $("").text(val).insertBefore(str).prevObject;
});

Among them, use the $.each() method to traverse the newData array, convert one element in the array to a jQuery object each time, and insert it in front of the placeholder. Use the prevObject property to obtain the new jQuery object after replacement and assign it to the str variable. The final result is:

"My name is Zhang San, I am 18 years old this year, and I was born in Beijing."

Compared with the replace() method, the replaceWith() method is more effective , the code is also more concise. However, it should be noted that if the replaced content contains tags, using the replaceWith() method will replace the entire tag and overwrite the original content.

3. Summary

jQuery provides a wealth of methods to operate page elements and strings, which can help us complete various tasks more easily. Among them, replacing placeholders is also a common requirement. This article introduces the use of jQuery to implement placeholder replacement, including the replace() method and replaceWith() method. In comparison, the replaceWith() method is more concise and more effective. In actual development, you can choose different methods to replace placeholders according to different needs.

The above is the detailed content of jquery replace placeholder. For more information, please follow other related articles on the PHP Chinese website!