7. A system for detecting an influence caused by changing a source code of an application from which a document object model (DOM) tree and cascading style sheets (CSSs) are extracted, the system comprising: a memory; and one or more processors, communicatively coupled to the memory, the one or more processors configured to: save one or more input operations of a user of the application, a DOM tree, and a CSS for each of one or more times that an instruction is received to check a screen state; emulate, after the source code is changed, the one or more input operations in an operation order, for each of the one or more times; acquire a DOM tree and CSS for each of the one or more times; compare the saved DOM tree and CSS with the acquired DOM tree and CSS for each of the one or more times; and output a result of the comparison.
7. A system for detecting an influence caused by changing a source code of an application from which a document object model (DOM) tree and cascading style sheets (CSSs) are extracted, the system comprising: a memory; and one or more processors, communicatively coupled to the memory, the one or more processors configured to: save one or more input operations of a user of the application, a DOM tree, and a CSS for each of one or more times that an instruction is received to check a screen state; emulate, after the source code is changed, the one or more input operations in an operation order, for each of the one or more times; acquire a DOM tree and CSS for each of the one or more times; compare the saved DOM tree and CSS with the acquired DOM tree and CSS for each of the one or more times; and output a result of the comparison. 8. The system of claim 7 , wherein the compare comprises: specifying, among CSS properties in at least one of the saved CSS and the acquired CSS, a first CSS property used for actual screen display at a specific time among the one or more times; specifying, among the CSS properties in the acquired CSS, a second CSS property used for actual screen display at the same time as the specific time; and comparing the first CSS property and the second CSS property.