How to limit the number of characters in jquery

With the rapid development of the Internet, more and more websites and applications involve character or word limit limits. For example, an e-commerce platform needs to limit the length of user names; a Weibo platform needs to limit the number of characters in a Weibo post; a news website needs to limit the number of characters in comments, etc. In response to this need, JQuery provides some simple methods to limit the number of characters or words in the input box or text box. This article will introduce some of the commonly used methods.

1. Count the number of characters or words in the input box or text box

We can use JQuery's val() function to get the value in the input box or text box, and then use The length property gets its length to count the number of characters or words. An example is as follows:

$("#input").on("input",function(){
    var text = $(this).val();
    var num = text.length;
    $("#count").text(num);
});

In this code, we use the input event. When the user enters any character in the input box, the event is triggered. Then we get the value of the input box and use the length attribute to get the character. quantity, and finally display the number of characters on the page.

2. Limit the number of characters or words in the input box or text box

In addition to counting the number of characters or words, we can also limit the number of characters or words in the input box or text box. We can use JQuery's val() function to intercept part of the string to achieve this function. An example is as follows:

$("#input").on("input",function(){
    var text = $(this).val();
    var limit = 10;//定义限制字符数
    if(text.length > limit){//超过限制字符数
        $(this).val(text.substr(0,limit));//截取固定长度的字符串
    }
});

In this code, we define a variable limit to specify the limit number of characters, and then determine whether the number of characters exceeds the limit number of characters in the input event. If it exceeds, use the substr() function Cut a fixed-length string to limit the number of characters or words in the input box or text box.

3. Display the remaining characters or words that can be entered

Sometimes, users need to know how many characters or words they can enter. We can use JQuery to display the remaining characters that can be entered. Or word count. An example is as follows:

var limit = 10;
$("#input").on("input",function(){
    var text = $(this).val();
    var count = limit - text.length;
    if(count >= 0){
        $("#message").text("您还可以输入 " + count + " 个字符");
    }else{
        $("#message").text("您已超出限制 " + Math.abs(count) + " 个字符");
    }
});

In this code, we define a variable limit to specify the limit number of characters, and then in the input event, we get the value in the input box or text box, and calculate what else can be entered How many characters are there? Prompt accordingly based on the calculation results.

In addition to the above three methods, there are other methods to limit the number of characters or words, such as using the maxlength attribute of HTML5, using plug-ins, etc. In short, JQuery provides many simple methods to limit the number of characters or words in an input box or text box. You can choose the appropriate method according to actual needs.

The above is the detailed content of How to limit the number of characters in jquery. For more information, please follow other related articles on the PHP Chinese website!