Javascript: type conversion

Javascript: type conversion When a variable is used in an expression, JavaScript automatically converts a type value to another type. That is to say, there can be different types of data combinations in the expression. Javascript completes the type conversion necessary to make the expression meaningful During computation. In JavaScript, type conversion is based on the priority of its operation. Generally, string operations have a higher priority, followed by floating point operations, integer operations, and logical operations. For example, if the expression "test" + 5 is used, convert the number 5 to the string "5" and append it to the string "test". The result is "test" + 5. Note: In all cases, when non-string operators use string operations, JavaScript converts their operators into strings: * Convert numeric values to corresponding string values. * Boolean values are converted to 1 and 0 to support numerical operations. * The null value is converted to the "null" of the string operation, Boolean false, or numeric 0. ========================================================== A function is a set of JavaScript code for a specific task. A value is usually returned. The function may have no parameters or multiple parameters. The parameter specifies the data to be processed by the function. Javascript provides three explicit type conversion functions: eval (), parseint (), and parsefloat (). Eval () function: converts a string expression to a numeric value. For example, the result of the statement Total = eval ("432.1*10") is total = 4321, which is about to assign the value 4321 to the total variable. Parseint () function: converts a string to an integer. The return value starts with the first character of the string. If the character does not start with an integer, 0 is returned. The parseint () function can also convert hexadecimal or decimal numbers. For example, parseint ("123xyz") returns 123, while parseint ("XYZ") returns 0. Parsefloat () function: similar to the parseint () function, it returns the first floating point number contained in the string. If the string does not start with a valid floating point number, 0 is returned. For example, parsefloat ("2.1e4xyz") returns 21000, while parsefloat ("XYZ") returns 0.