JavaScript Tips (Fourth episode)

Javascript| Tips

Fourth episode how to use an operation function

This is a special built-in function eval includes an operand for its arguments, an operand, and a value to be returned. This function is useful for computing a numeric string that is represented, for example, the value entered from form is always a string, but you may want to do it, so what should I do?
The following example packages the input text field, applies the Operation function, and displays the result of another block. If you hit a numeric expression in the first field, and the button is pressed, the expression is opened to the operation,

function Compute (obj) {
Obj.result.value = eval (obj.expr.value)
}

Enter An expression:
Result: >