Js achieves adaptive height of text boxes based on input content

We can see that many websites can control the Textarea input box to increase according to the user input content. Below I will summarize the two text boxes based on the input content adaptive height examples.

Use jquery's autoTextarea Method

JS Code, default parameters and calls:

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// Default parameters $ (". ChackTextarea-area"). autoTextarea ({ MaxHeight: 220, MinHeight: $ (this). height () })

Example

The Code is as follows:

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(Function ($ ){ $. Fn. autoTextarea = function (options ){ Var defaults = { MaxHeight: null, // whether the text box is automatically supported. Default Value: null. If the text box is not automatically supported, a value must be entered. This value is used as the maximum height of the text box automatically supported. MinHeight: $ (this). height () // The default minimum height, that is, the initial height of the text box. When the content height is smaller than this height, the text is displayed at this height. }; Var opts = $. extend ({}, defaults, options ); Return $ (this). each (function (){ $ (This). bind ("paste cut keydown keyup focus blur", function (){ Var height, style = this. style; This. style. height = opts. minHeight + 'px '; If (this. scrollHeight & gt; opts. minHeight ){ If (opts. maxHeight & amp; this. scrollHeight & gt; opts. maxHeight ){ Height = opts. maxHeight; Style. overflowY = 'scroll '; } Else { Height = this. scrollHeight; Style. overflowY = 'ddn '; } Style. height = height + 'px '; } }); }); }; }) (JQuery );

Js achieves adaptive height of text boxes based on input content

The Code is as follows:

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/** * The text box adaptive height based on the input content **/ Var autoTextarea = function (elem, extra, maxHeight ){ Extra = extra | 20; Var isFirefox = !! Document. getBoxObjectFor | 'initnerscreenx' in window, IsOpera = !! Window. opera &&!! Window. opera. toString (). indexOf ('Opera '), AddEvent = function (type, callback ){ Elem. addEventListener? Elem. addEventListener (type, callback, false ): Elem. attachEvent ('on' + type, callback ); }, GetStyle = elem. currentStyle? Function (name ){ Var val = elem. currentStyle [name]; If (name = 'height' & val. search (/px/I )! = 1 ){ Var rect = elem. getBoundingClientRect (); Return rect. bottom-rect. top- ParseFloat (getStyle ('addingtop '))- ParseFloat (getStyle ('paddingbottom ') + 'px '; }; Return val; }: Function (name ){ Return getComputedStyle (elem, null) [name]; }, MinHeight = parseFloat (getStyle ('height ')); Elem. style. maxHeight = elem. style. resize = 'none '; Var change = function (){ Var scrollTop, height, Padding = 0, Style = elem. style; If (elem. _ length = elem. value. length) return; Elem. _ length = elem. value. length; If (! IsFirefox &&! IsOpera ){ Padding = parseInt (getStyle ('paddingtop ') + parseInt (getStyle ('paddingbottom ')); }; ScrollTop = document. body. scrollTop | document.doc umentElement. scrollTop; Elem. style. height = minHeight + 'px '; If (elem. scrollHeight> minHeight ){ If (maxHeight & elem. scrollHeight> maxHeight ){ Height = maxHeight-padding; Style. overflowY = 'auto '; } Else { Height = elem. scrollHeight-padding; Style. overflowY = 'ddn '; }; Style. height = height + extra + 'px '; ScrollTop + = parseInt (style. height)-elem. currHeight; Document. body. scrollTop = scrollTop; Document.doc umentElement. scrollTop = scrollTop; Elem. currHeight = parseInt (style. height ); }; }; AddEvent ('propertychange', change ); AddEvent ('input', change ); AddEvent ('focal ', change ); Change (); };

The call method is as follows (textarea_id is the id value of textarea ):

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AutoTextarea (document. getElementById ('textarea _ id '));