dateObjectName is either the name of a date object or a property of an existing object. timevalue is an integer or a property of an existing object, representing the number of milliseconds since the epoch (1 January 1970 00:00:00).
Evaluates an expression after a specified number of milliseconds have elapsed.
语法
timeoutID=setTimeout(expression, msec)
timeoutID is an identifier that is used only to cancel the evaluation with the clearTimeout method. expression is a string expression or a property of an existing object. msec is a numeric value, numeric string, or a property of an existing object in millisecond units.
The setTimeout method evaluates an expression after a specified amount of time. It does not evaluate the expression repeatedly. For example, if a setTimeout method specifies 5 seconds, the expression is evaluated after 5 seconds, not every 5 seconds.
例子
Example 1. The following example displays an alert message 5 seconds (5,000 milliseconds) after the user clicks a button. If the user clicks the second button before the alert message is displayed, the timeout is canceled and the alert does not display.
Example 2. The following example displays the current time in a text object. The showtime() function, which is called recursively, uses the setTimeout method update the time every second.
dateObjectName is either the name of a date object or a property of an existing object. yearValue is an integer greater than 1900 or a property of an existing object.
The sin method returns a numeric value between -1 and 1, which represents the sine of the angle.
例子
//Displays the value 1document.write("The sine of pi/2 radians is " + Math.sin(Math.PI/2))//Displays the value 1.224606353822377e-016document.write("<P>The sine of pi radians is " + Math.sin(Math.PI))//Displays the value 0document.write("<P>The sine of 0 radians is " + Math.sin(0))
If the value of number is outside the suggested range, the return value is always 0.
例子
//Displays the value 3document.write("The square root of 9 is " + Math.sqrt(9))//Displays the value 1.414213562373095document.write("<P>The square root of 2 is " + Math.sqrt(2))//Displays the value 0 because the argument is out of rangedocument.write("<P>The square root of -1 is " + Math.sqrt(-1))
Specifies a priority or transient message in the status bar at the bottom of the window, such as the message that appears when a mouseOver event occurs over an anchor.
语法
windowReference.status
windowReference is a valid way of referring to a window, as described in the window object.
Do not confuse the status property with the defaultStatus property. The defaultStatus property reflects the default message displayed in the status bar.
You can set the status property at any time. You must return true if you want to set the status property in the onMouseOver event handler.
例子
Suppose you have created a JavaScript function called pickRandomURL() that lets you select a URL at random. You can use the onClick event handler of an anchor to specify a value for the HREF attribute of the anchor dynamically, and the onMouseOver event handler to specify a custom message for the window in the status property:
In the above example, the status property of the window is assigned to the window's self property, as self.status. As this example shows, you must return true to set the status property in the onMouseOver event handler.
None. Built-in objects do not have event handlers.
例子
The following statement creates a string variable.
var last_name = "Schaefer"The following statements evaluate to 8, "SCHAEFER", and "schaefer": last_name.lengthlast_name.toUpperCase()last_name.toLowerCase()
Use the sub method with the write or writeln methods to format and display a string in a document.
例子
The following example uses the sub and sup methods to format a string:
var superText="superscript"var subText="subscript"document.write("This is what a " + superText.sup() + " looks like.")document.write("<P>This is what a " + subText.sub() + " looks like.")
The previous example produces the same output as the following htm:
This is what a <SUP>superscript</SUP> looks like.<P>This is what a <SUB>subscript</SUB> looks like.
The submit method submits the specified form. It performs the same action as a submit button.
Use the submit method to send data back to an http server. The submit method returns the data using either "get" or "post", as specified in the method property.
例子
The following example submits a form called musicChoice:
document.musicChoice.submit()
If musicChoice is the first form created, you also can submit it as follows:
NAME="submitName" specifies the name of the submit object. You can access this value using the name property. VALUE="buttonText" specifies the label to display on the button face. You can access this value using the value property.
submitName is the value of the NAME attribute of a submit object. formName is either the value of the NAME attribute of a form object or an element in the forms array. index is an integer representing a submit object on a form. propertyName is one of the properties listed below. methodName is one of the methods listed below.
A submit object is a form element and must be defined within a <FORM> tag.
Clicking a submit button submits a form to the URL specified by the form's action property. This action always loads a new page into the client; it may be the same as the current page, if the action so specifies or is not specified.
The submit button's onClick event handler cannot prevent a form from being submitted; instead, use the form's onSubmit event handler or use the submit method instead of a submit object. See the 例子 for the form object.