jquery forced conversion into numbers

In JavaScript, numbers and strings are two different data types. And sometimes we need to convert the string type into a numeric type. When using jQuery, you often need to read the value in the form input box or obtain the attribute value of some elements. In this case, you need to force the obtained string into a number. Here's how to cast in jQuery.

1. Use JavaScript’s parseInt() function

In JavaScript, we can use the parseInt() function to convert the string type into a numeric type. This function accepts a string parameter and returns an integer. The sample code is as follows:

var str = "123";
var num = parseInt(str);
console.log(num); // 输出 123

In jQuery, we can use the same method to coerce strings into numbers. For example, the following code uses parseInt() to convert the value of a form input box into a numeric type:

var num = parseInt($('#input').val());

2. Use JavaScript's parseFloat() function

If you need to convert a string type float To convert points into numeric type, you can use the parseFloat() function. This function accepts a string parameter and returns a floating point number.

var str = "3.14";
var num = parseFloat(str);
console.log(num); // 输出 3.14

In jQuery, we can also use this function to force the floating-point string to a numeric type.

var num = parseFloat($('#input').val());

It should be noted that the parseFloat() function can only convert decimal floating point strings into numeric types. If the string is not a floating point number, this function will return NaN (Not a Number), which is not a number.

3. Use the plus sign operator

In addition to using the parseInt() and parseFloat() functions, you can also use the plus sign operator ( ) to convert a string into a numeric type. This method only works with string variables and string constants.

var str = "100";
var num = +str;
console.log(num); // 输出 100

Similarly, we can also apply this method to jQuery statements.

var num = +$('#input').val();

It should be noted that if the string is not a pure number, this method will return NaN.

To sum up, it can be seen that casting in jQuery is actually casting in JavaScript. Using the above three methods, you can easily convert the string type into a numeric type and can be applied to jQuery statements. The choice of these methods depends on specific needs and needs to be selected according to different situations.

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